[PATCH v6 7/8] LoongArch: Add ORC stack unwinder support

From: Tiezhu Yang
Date: Tue Jan 30 2024 - 01:19:30 EST

The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
similar in concept to a DWARF unwinder. The difference is that the format
of the ORC data is much simpler than DWARF, which in turn allows the ORC
unwinder to be much simpler and faster.

The ORC data consists of unwind tables which are generated by objtool.
After analyzing all the code paths of a .o file, it determines information
about the stack state at each instruction address in the file and outputs
that information to the .orc_unwind and .orc_unwind_ip sections.

The per-object ORC sections are combined at link time and are sorted and
post-processed at boot time. The unwinder uses the resulting data to
correlate instruction addresses with their stack states at run time.

Most of the logic are similar with x86, in order to get ra info before ra
is saved into stack, add ra_reg and ra_offset into orc_entry. At the same
time, modify some arch-specific code to silence the objtool warnings.

Co-developed-by: Jinyang He <hejinyang@xxxxxxxxxxx>
Signed-off-by: Jinyang He <hejinyang@xxxxxxxxxxx>
Co-developed-by: Youling Tang <tangyouling@xxxxxxxxxxx>
Signed-off-by: Youling Tang <tangyouling@xxxxxxxxxxx>
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
---
arch/loongarch/Kconfig | 2 +
arch/loongarch/Kconfig.debug | 11 +
arch/loongarch/Makefile | 23 +-
arch/loongarch/include/asm/Kbuild | 2 +
arch/loongarch/include/asm/bug.h | 1 +
arch/loongarch/include/asm/exception.h | 2 +
arch/loongarch/include/asm/module.h | 7 +
arch/loongarch/include/asm/orc_header.h | 18 +
arch/loongarch/include/asm/orc_lookup.h | 31 ++
arch/loongarch/include/asm/orc_types.h | 58 +++
arch/loongarch/include/asm/stackframe.h | 3 +
arch/loongarch/include/asm/unwind.h | 20 +-
arch/loongarch/include/asm/unwind_hints.h | 28 ++
arch/loongarch/kernel/Makefile | 4 +
arch/loongarch/kernel/entry.S | 5 +
arch/loongarch/kernel/fpu.S | 7 +
arch/loongarch/kernel/genex.S | 6 +
arch/loongarch/kernel/lbt.S | 2 +
arch/loongarch/kernel/mcount_dyn.S | 6 +
arch/loongarch/kernel/module.c | 22 +-
arch/loongarch/kernel/relocate_kernel.S | 8 +-
arch/loongarch/kernel/rethook_trampoline.S | 1 +
arch/loongarch/kernel/setup.c | 2 +
arch/loongarch/kernel/stacktrace.c | 1 +
arch/loongarch/kernel/traps.c | 42 +-
arch/loongarch/kernel/unwind_orc.c | 516 +++++++++++++++++++++
arch/loongarch/kernel/vmlinux.lds.S | 3 +
arch/loongarch/kvm/switch.S | 9 +-
arch/loongarch/lib/clear_user.S | 2 +
arch/loongarch/lib/copy_user.S | 2 +
arch/loongarch/lib/memcpy.S | 2 +
arch/loongarch/lib/memset.S | 2 +
arch/loongarch/mm/tlb.c | 27 +-
arch/loongarch/mm/tlbex.S | 9 +
arch/loongarch/vdso/Makefile | 1 +
include/linux/compiler.h | 9 +
scripts/Makefile | 7 +-
37 files changed, 859 insertions(+), 42 deletions(-)
create mode 100644 arch/loongarch/include/asm/orc_header.h
create mode 100644 arch/loongarch/include/asm/orc_lookup.h
create mode 100644 arch/loongarch/include/asm/orc_types.h
create mode 100644 arch/loongarch/include/asm/unwind_hints.h
create mode 100644 arch/loongarch/kernel/unwind_orc.c

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 10959e6c3583..17be0bff0f40 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -134,6 +134,7 @@ config LOONGARCH
select HAVE_KVM
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
+ select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
select HAVE_PCI
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
@@ -146,6 +147,7 @@ config LOONGARCH
select HAVE_SAMPLE_FTRACE_DIRECT
select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
select HAVE_SETUP_PER_CPU_AREA if NUMA
+ select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_TIF_NOHZ
diff --git a/arch/loongarch/Kconfig.debug b/arch/loongarch/Kconfig.debug
index 8d36aab53008..98d60630c3d4 100644
--- a/arch/loongarch/Kconfig.debug
+++ b/arch/loongarch/Kconfig.debug
@@ -26,4 +26,15 @@ config UNWINDER_PROLOGUE
Some of the addresses it reports may be incorrect (but better than the
Guess unwinder).

+config UNWINDER_ORC
+ bool "ORC unwinder"
+ select OBJTOOL
+ help
+ This option enables the ORC (Oops Rewind Capability) unwinder for
+ unwinding kernel stack traces. It uses a custom data format which is
+ a simplified version of the DWARF Call Frame Information standard.
+
+ Enabling this option will increase the kernel's runtime memory usage
+ by roughly 2-4MB, depending on your kernel config.
+
endchoice
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 983aa2b1629a..e3bc02fb7fdc 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -26,6 +26,18 @@ endif
32bit-emul = elf32loongarch
64bit-emul = elf64loongarch

+ifdef CONFIG_UNWINDER_ORC
+orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
+orc_hash_sh := $(srctree)/scripts/orc_hash.sh
+targets += $(orc_hash_h)
+quiet_cmd_orc_hash = GEN $@
+ cmd_orc_hash = mkdir -p $(dir $@); \
+ $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
+$(orc_hash_h): $(srctree)/arch/loongarch/include/asm/orc_types.h $(orc_hash_sh) FORCE
+ $(call if_changed,orc_hash)
+archprepare: $(orc_hash_h)
+endif
+
ifdef CONFIG_DYNAMIC_FTRACE
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
CC_FLAGS_FTRACE := -fpatchable-function-entry=2
@@ -72,8 +84,6 @@ KBUILD_CFLAGS_KERNEL += $(call cc-option,-mdirect-extern-access)
KBUILD_CFLAGS_KERNEL += $(call cc-option,-fdirect-access-external-data)
KBUILD_AFLAGS_MODULE += $(call cc-option,-fno-direct-access-external-data)
KBUILD_CFLAGS_MODULE += $(call cc-option,-fno-direct-access-external-data)
-KBUILD_AFLAGS_MODULE += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
-KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
else
cflags-y += $(call cc-option,-mno-explicit-relocs)
KBUILD_AFLAGS_KERNEL += -Wa,-mla-global-with-pcrel
@@ -82,6 +92,15 @@ KBUILD_AFLAGS_MODULE += -Wa,-mla-global-with-abs
KBUILD_CFLAGS_MODULE += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs
endif

+KBUILD_AFLAGS += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
+KBUILD_CFLAGS += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
+KBUILD_AFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+KBUILD_CFLAGS += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+
+ifdef CONFIG_OBJTOOL
+KBUILD_CFLAGS += -fno-jump-tables
+endif
+
KBUILD_RUSTFLAGS_MODULE += -Crelocation-model=pic

ifeq ($(CONFIG_RELOCATABLE),y)
diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild
index 93783fa24f6e..a97c0edbb866 100644
--- a/arch/loongarch/include/asm/Kbuild
+++ b/arch/loongarch/include/asm/Kbuild
@@ -1,4 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
+generated-y += orc_hash.h
+
generic-y += dma-contiguous.h
generic-y += mcs_spinlock.h
generic-y += parport.h
diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index d4ca3ba25418..08388876ade4 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -44,6 +44,7 @@
do { \
instrumentation_begin(); \
__BUG_FLAGS(BUGFLAG_WARNING|(flags)); \
+ annotate_reachable(); \
instrumentation_end(); \
} while (0)

diff --git a/arch/loongarch/include/asm/exception.h b/arch/loongarch/include/asm/exception.h
index af74a3fdcad1..c6d20736fd92 100644
--- a/arch/loongarch/include/asm/exception.h
+++ b/arch/loongarch/include/asm/exception.h
@@ -6,6 +6,8 @@
#include <asm/ptrace.h>
#include <linux/kprobes.h>

+extern void *exception_table[];
+
void show_registers(struct pt_regs *regs);

asmlinkage void cache_parity_error(void);
diff --git a/arch/loongarch/include/asm/module.h b/arch/loongarch/include/asm/module.h
index 2ecd82bb64e1..f33f3fd32ecc 100644
--- a/arch/loongarch/include/asm/module.h
+++ b/arch/loongarch/include/asm/module.h
@@ -6,6 +6,7 @@
#define _ASM_MODULE_H

#include <asm/inst.h>
+#include <asm/orc_types.h>
#include <asm-generic/module.h>

#define RELA_STACK_DEPTH 16
@@ -21,6 +22,12 @@ struct mod_arch_specific {
struct mod_section plt;
struct mod_section plt_idx;

+#ifdef CONFIG_UNWINDER_ORC
+ unsigned int num_orcs;
+ int *orc_unwind_ip;
+ struct orc_entry *orc_unwind;
+#endif
+
/* For CONFIG_DYNAMIC_FTRACE */
struct plt_entry *ftrace_trampolines;
};
diff --git a/arch/loongarch/include/asm/orc_header.h b/arch/loongarch/include/asm/orc_header.h
new file mode 100644
index 000000000000..f9d509c3fd70
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_header.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _ORC_HEADER_H
+#define _ORC_HEADER_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+#include <asm/orc_hash.h>
+
+/*
+ * The header is currently a 20-byte hash of the ORC entry definition; see
+ * scripts/orc_hash.sh.
+ */
+#define ORC_HEADER \
+ __used __section(".orc_header") __aligned(4) \
+ static const u8 orc_header[] = { ORC_HASH }
+
+#endif /* _ORC_HEADER_H */
diff --git a/arch/loongarch/include/asm/orc_lookup.h b/arch/loongarch/include/asm/orc_lookup.h
new file mode 100644
index 000000000000..b02e6357def4
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_lookup.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_LOOKUP_H
+#define _ORC_LOOKUP_H
+
+/*
+ * This is a lookup table for speeding up access to the .orc_unwind table.
+ * Given an input address offset, the corresponding lookup table entry
+ * specifies a subset of the .orc_unwind table to search.
+ *
+ * Each block represents the end of the previous range and the start of the
+ * next range. An extra block is added to give the last range an end.
+ *
+ * The block size should be a power of 2 to avoid a costly 'div' instruction.
+ *
+ * A block size of 256 was chosen because it roughly doubles unwinder
+ * performance while only adding ~5% to the ORC data footprint.
+ */
+#define LOOKUP_BLOCK_ORDER 8
+#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER)
+
+#ifndef LINKER_SCRIPT
+
+extern unsigned int orc_lookup[];
+extern unsigned int orc_lookup_end[];
+
+#define LOOKUP_START_IP (unsigned long)_stext
+#define LOOKUP_STOP_IP (unsigned long)_etext
+
+#endif /* LINKER_SCRIPT */
+
+#endif /* _ORC_LOOKUP_H */
diff --git a/arch/loongarch/include/asm/orc_types.h b/arch/loongarch/include/asm/orc_types.h
new file mode 100644
index 000000000000..caf1f71a1057
--- /dev/null
+++ b/arch/loongarch/include/asm/orc_types.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and FP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED 0
+#define ORC_REG_PREV_SP 1
+#define ORC_REG_SP 2
+#define ORC_REG_FP 3
+#define ORC_REG_MAX 4
+
+#define ORC_TYPE_UNDEFINED 0
+#define ORC_TYPE_END_OF_STACK 1
+#define ORC_TYPE_CALL 2
+#define ORC_TYPE_REGS 3
+#define ORC_TYPE_REGS_PARTIAL 4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard. It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder. It tells the
+ * unwinder how to find the previous SP and FP (and sometimes entry regs) on
+ * the stack for a given code address. Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+ s16 sp_offset;
+ s16 fp_offset;
+ s16 ra_offset;
+ unsigned int sp_reg:4;
+ unsigned int fp_reg:4;
+ unsigned int ra_reg:4;
+ unsigned int type:3;
+ unsigned int signal:1;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */
diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/include/asm/stackframe.h
index 4fb1e6408b98..45b507a7b06f 100644
--- a/arch/loongarch/include/asm/stackframe.h
+++ b/arch/loongarch/include/asm/stackframe.h
@@ -13,6 +13,7 @@
#include <asm/asm-offsets.h>
#include <asm/loongarch.h>
#include <asm/thread_info.h>
+#include <asm/unwind_hints.h>

/* Make the addition of cfi info a little easier. */
.macro cfi_rel_offset reg offset=0 docfi=0
@@ -162,6 +163,7 @@
li.w t0, CSR_CRMD_WE
csrxchg t0, t0, LOONGARCH_CSR_CRMD
#endif
+ UNWIND_HINT_REGS
.endm

.macro SAVE_ALL docfi=0
@@ -219,6 +221,7 @@

.macro RESTORE_SP_AND_RET docfi=0
cfi_ld sp, PT_R3, \docfi
+ UNWIND_HINT_FUNC
ertn
.endm

diff --git a/arch/loongarch/include/asm/unwind.h b/arch/loongarch/include/asm/unwind.h
index b9dce87afd2e..40a6763c5aec 100644
--- a/arch/loongarch/include/asm/unwind.h
+++ b/arch/loongarch/include/asm/unwind.h
@@ -16,6 +16,7 @@
enum unwinder_type {
UNWINDER_GUESS,
UNWINDER_PROLOGUE,
+ UNWINDER_ORC,
};

struct unwind_state {
@@ -24,7 +25,7 @@ struct unwind_state {
struct task_struct *task;
bool first, error, reset;
int graph_idx;
- unsigned long sp, pc, ra;
+ unsigned long sp, fp, pc, ra;
};

bool default_next_frame(struct unwind_state *state);
@@ -61,14 +62,17 @@ static __always_inline void __unwind_start(struct unwind_state *state,
state->sp = regs->regs[3];
state->pc = regs->csr_era;
state->ra = regs->regs[1];
+ state->fp = regs->regs[22];
} else if (task && task != current) {
state->sp = thread_saved_fp(task);
state->pc = thread_saved_ra(task);
state->ra = 0;
+ state->fp = 0;
} else {
state->sp = (unsigned long)__builtin_frame_address(0);
state->pc = (unsigned long)__builtin_return_address(0);
state->ra = 0;
+ state->fp = 0;
}
state->task = task;
get_stack_info(state->sp, state->task, &state->stack_info);
@@ -77,6 +81,18 @@ static __always_inline void __unwind_start(struct unwind_state *state,

static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
{
- return unwind_done(state) ? 0 : state->pc;
+ if (unwind_done(state))
+ return 0;
+
+ return __kernel_text_address(state->pc) ? state->pc : 0;
}
+
+#ifdef CONFIG_UNWINDER_ORC
+void unwind_init(void);
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size);
+#else
+static inline void unwind_init(void) {}
+static inline void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size) {}
+#endif
+
#endif /* _ASM_UNWIND_H */
diff --git a/arch/loongarch/include/asm/unwind_hints.h b/arch/loongarch/include/asm/unwind_hints.h
new file mode 100644
index 000000000000..82443fed3167
--- /dev/null
+++ b/arch/loongarch/include/asm/unwind_hints.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_LOONGARCH_UNWIND_HINTS_H
+#define _ASM_LOONGARCH_UNWIND_HINTS_H
+
+#include <linux/objtool.h>
+#include <asm/orc_types.h>
+
+#ifdef __ASSEMBLY__
+
+.macro UNWIND_HINT_UNDEFINED
+ UNWIND_HINT type=UNWIND_HINT_TYPE_UNDEFINED
+.endm
+
+.macro UNWIND_HINT_EMPTY
+ UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL
+.endm
+
+.macro UNWIND_HINT_REGS
+ UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_REGS
+.endm
+
+.macro UNWIND_HINT_FUNC
+ UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_CALL
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_LOONGARCH_UNWIND_HINTS_H */
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 3c808c680370..3a7620b66bc6 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -3,6 +3,8 @@
# Makefile for the Linux/LoongArch kernel.
#

+OBJECT_FILES_NON_STANDARD_head.o := y
+
extra-y := vmlinux.lds

obj-y += head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
@@ -21,6 +23,7 @@ obj-$(CONFIG_ARCH_STRICT_ALIGN) += unaligned.o

CFLAGS_module.o += $(call cc-option,-Wno-override-init,)
CFLAGS_syscall.o += $(call cc-option,-Wno-override-init,)
+CFLAGS_traps.o += $(call cc-option,-Wno-override-init,)
CFLAGS_perf_event.o += $(call cc-option,-Wno-override-init,)

ifdef CONFIG_FUNCTION_TRACER
@@ -62,6 +65,7 @@ obj-$(CONFIG_CRASH_DUMP) += crash_dump.o

obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o
obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
+obj-$(CONFIG_UNWINDER_ORC) += unwind_orc.o

obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S
index 1ec8e4c4cc2b..48e7e34e355e 100644
--- a/arch/loongarch/kernel/entry.S
+++ b/arch/loongarch/kernel/entry.S
@@ -14,11 +14,13 @@
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/thread_info.h>
+#include <asm/unwind_hints.h>

.text
.cfi_sections .debug_frame
.align 5
SYM_CODE_START(handle_syscall)
+ UNWIND_HINT_UNDEFINED
csrrd t0, PERCPU_BASE_KS
la.pcrel t1, kernelsp
add.d t1, t1, t0
@@ -57,6 +59,7 @@ SYM_CODE_START(handle_syscall)
cfi_st fp, PT_R22

SAVE_STATIC
+ UNWIND_HINT_REGS

#ifdef CONFIG_KGDB
li.w t1, CSR_CRMD_WE
@@ -75,6 +78,7 @@ SYM_CODE_END(handle_syscall)
_ASM_NOKPROBE(handle_syscall)

SYM_CODE_START(ret_from_fork)
+ UNWIND_HINT_REGS
bl schedule_tail # a0 = struct task_struct *prev
move a0, sp
bl syscall_exit_to_user_mode
@@ -84,6 +88,7 @@ SYM_CODE_START(ret_from_fork)
SYM_CODE_END(ret_from_fork)

SYM_CODE_START(ret_from_kernel_thread)
+ UNWIND_HINT_REGS
bl schedule_tail # a0 = struct task_struct *prev
move a0, s1
jirl ra, s0, 0
diff --git a/arch/loongarch/kernel/fpu.S b/arch/loongarch/kernel/fpu.S
index 4382e36ae3d4..69a85f2479fb 100644
--- a/arch/loongarch/kernel/fpu.S
+++ b/arch/loongarch/kernel/fpu.S
@@ -15,6 +15,7 @@
#include <asm/fpregdef.h>
#include <asm/loongarch.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

#define FPU_REG_WIDTH 8
#define LSX_REG_WIDTH 16
@@ -526,3 +527,9 @@ SYM_FUNC_END(_restore_lasx_context)
.L_fpu_fault:
li.w a0, -EFAULT # failure
jr ra
+
+#ifdef CONFIG_CPU_HAS_LBT
+STACK_FRAME_NON_STANDARD _restore_fp
+STACK_FRAME_NON_STANDARD _restore_lsx
+STACK_FRAME_NON_STANDARD _restore_lasx
+#endif
diff --git a/arch/loongarch/kernel/genex.S b/arch/loongarch/kernel/genex.S
index 2bb3aa2dcfcb..86d5d90ebefe 100644
--- a/arch/loongarch/kernel/genex.S
+++ b/arch/loongarch/kernel/genex.S
@@ -32,6 +32,7 @@ SYM_FUNC_START(__arch_cpu_idle)
SYM_FUNC_END(__arch_cpu_idle)

SYM_CODE_START(handle_vint)
+ UNWIND_HINT_UNDEFINED
BACKUP_T0T1
SAVE_ALL
la_abs t1, __arch_cpu_idle
@@ -49,6 +50,7 @@ SYM_CODE_START(handle_vint)
SYM_CODE_END(handle_vint)

SYM_CODE_START(except_vec_cex)
+ UNWIND_HINT_UNDEFINED
b cache_parity_error
SYM_CODE_END(except_vec_cex)

@@ -67,6 +69,7 @@ SYM_CODE_END(except_vec_cex)
.macro BUILD_HANDLER exception handler prep
.align 5
SYM_CODE_START(handle_\exception)
+ UNWIND_HINT_UNDEFINED
666:
BACKUP_T0T1
SAVE_ALL
@@ -77,7 +80,9 @@ SYM_CODE_END(except_vec_cex)
668:
RESTORE_ALL_AND_RET
SYM_CODE_END(handle_\exception)
+ .pushsection ".data", "aw", %progbits
SYM_DATA(unwind_hint_\exception, .word 668b - 666b)
+ .popsection
.endm

BUILD_HANDLER ade ade badv
@@ -94,6 +99,7 @@ SYM_CODE_END(except_vec_cex)
BUILD_HANDLER reserved reserved none /* others */

SYM_CODE_START(handle_sys)
+ UNWIND_HINT_UNDEFINED
la_abs t0, handle_syscall
jr t0
SYM_CODE_END(handle_sys)
diff --git a/arch/loongarch/kernel/lbt.S b/arch/loongarch/kernel/lbt.S
index 9c75120a26d8..aaea5768c99e 100644
--- a/arch/loongarch/kernel/lbt.S
+++ b/arch/loongarch/kernel/lbt.S
@@ -11,6 +11,7 @@
#include <asm/asm-offsets.h>
#include <asm/errno.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

#define SCR_REG_WIDTH 8

@@ -149,6 +150,7 @@ SYM_FUNC_START(_restore_ftop_context)
li.w a0, 0 # success
jr ra
SYM_FUNC_END(_restore_ftop_context)
+STACK_FRAME_NON_STANDARD _restore_ftop_context

.L_lbt_fault:
li.w a0, -EFAULT # failure
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S
index 482aa553aa2d..0c65cf09110c 100644
--- a/arch/loongarch/kernel/mcount_dyn.S
+++ b/arch/loongarch/kernel/mcount_dyn.S
@@ -73,6 +73,7 @@ SYM_FUNC_START(ftrace_stub)
SYM_FUNC_END(ftrace_stub)

SYM_CODE_START(ftrace_common)
+ UNWIND_HINT_UNDEFINED
PTR_ADDI a0, ra, -8 /* arg0: ip */
move a1, t0 /* arg1: parent_ip */
la.pcrel t1, function_trace_op
@@ -113,12 +114,14 @@ ftrace_common_return:
SYM_CODE_END(ftrace_common)

SYM_CODE_START(ftrace_caller)
+ UNWIND_HINT_UNDEFINED
ftrace_regs_entry allregs=0
b ftrace_common
SYM_CODE_END(ftrace_caller)

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
SYM_CODE_START(ftrace_regs_caller)
+ UNWIND_HINT_UNDEFINED
ftrace_regs_entry allregs=1
b ftrace_common
SYM_CODE_END(ftrace_regs_caller)
@@ -126,6 +129,7 @@ SYM_CODE_END(ftrace_regs_caller)

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
SYM_CODE_START(ftrace_graph_caller)
+ UNWIND_HINT_UNDEFINED
PTR_L a0, sp, PT_ERA
PTR_ADDI a0, a0, -8 /* arg0: self_addr */
PTR_ADDI a1, sp, PT_R1 /* arg1: parent */
@@ -134,6 +138,7 @@ SYM_CODE_START(ftrace_graph_caller)
SYM_CODE_END(ftrace_graph_caller)

SYM_CODE_START(return_to_handler)
+ UNWIND_HINT_UNDEFINED
/* Save return value regs */
PTR_ADDI sp, sp, -FGRET_REGS_SIZE
PTR_S a0, sp, FGRET_REGS_A0
@@ -155,6 +160,7 @@ SYM_CODE_END(return_to_handler)

#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
SYM_CODE_START(ftrace_stub_direct_tramp)
+ UNWIND_HINT_UNDEFINED
jr t0
SYM_CODE_END(ftrace_stub_direct_tramp)
#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
diff --git a/arch/loongarch/kernel/module.c b/arch/loongarch/kernel/module.c
index b13b2858fe39..c7d0338d12c1 100644
--- a/arch/loongarch/kernel/module.c
+++ b/arch/loongarch/kernel/module.c
@@ -20,6 +20,7 @@
#include <linux/kernel.h>
#include <asm/alternative.h>
#include <asm/inst.h>
+#include <asm/unwind.h>

static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
{
@@ -515,15 +516,28 @@ static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs, struct module *mod)
{
- const Elf_Shdr *s, *se;
const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+ const Elf_Shdr *s, *alt = NULL, *orc = NULL, *orc_ip = NULL, *ftrace = NULL;

- for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
+ for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (!strcmp(".altinstructions", secstrs + s->sh_name))
- apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size);
+ alt = s;
+ if (!strcmp(".orc_unwind", secstrs + s->sh_name))
+ orc = s;
+ if (!strcmp(".orc_unwind_ip", secstrs + s->sh_name))
+ orc_ip = s;
if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
- module_init_ftrace_plt(hdr, s, mod);
+ ftrace = s;
}

+ if (alt)
+ apply_alternatives((void *)alt->sh_addr, (void *)alt->sh_addr + alt->sh_size);
+
+ if (orc && orc_ip)
+ unwind_module_init(mod, (void *)orc_ip->sh_addr, orc_ip->sh_size, (void *)orc->sh_addr, orc->sh_size);
+
+ if (ftrace)
+ module_init_ftrace_plt(hdr, ftrace, mod);
+
return 0;
}
diff --git a/arch/loongarch/kernel/relocate_kernel.S b/arch/loongarch/kernel/relocate_kernel.S
index f49f6b053763..268e8f7240b6 100644
--- a/arch/loongarch/kernel/relocate_kernel.S
+++ b/arch/loongarch/kernel/relocate_kernel.S
@@ -15,6 +15,7 @@
#include <asm/addrspace.h>

SYM_CODE_START(relocate_new_kernel)
+ UNWIND_HINT_UNDEFINED
/*
* a0: EFI boot flag for the new kernel
* a1: Command line pointer for the new kernel
@@ -90,6 +91,7 @@ SYM_CODE_END(relocate_new_kernel)
* then start at the entry point from LOONGARCH_IOCSR_MBUF0.
*/
SYM_CODE_START(kexec_smp_wait)
+ UNWIND_HINT_UNDEFINED
1: li.w t0, 0x100 /* wait for init loop */
2: addi.w t0, t0, -1 /* limit mailbox access */
bnez t0, 2b
@@ -106,6 +108,6 @@ SYM_CODE_END(kexec_smp_wait)

relocate_new_kernel_end:

-SYM_DATA_START(relocate_new_kernel_size)
- PTR relocate_new_kernel_end - relocate_new_kernel
-SYM_DATA_END(relocate_new_kernel_size)
+.pushsection ".data", "aw", %progbits
+SYM_DATA(relocate_new_kernel_size, .long relocate_new_kernel_end - relocate_new_kernel)
+.popsection
diff --git a/arch/loongarch/kernel/rethook_trampoline.S b/arch/loongarch/kernel/rethook_trampoline.S
index bd5772c96338..d4ceb2fa2a5c 100644
--- a/arch/loongarch/kernel/rethook_trampoline.S
+++ b/arch/loongarch/kernel/rethook_trampoline.S
@@ -76,6 +76,7 @@
.endm

SYM_CODE_START(arch_rethook_trampoline)
+ UNWIND_HINT_UNDEFINED
addi.d sp, sp, -PT_SIZE
save_all_base_regs

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index edf2bba80130..3e860bd8d500 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -47,6 +47,7 @@
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/time.h>
+#include <asm/unwind.h>

#define SMBIOS_BIOSSIZE_OFFSET 0x09
#define SMBIOS_BIOSEXTERN_OFFSET 0x13
@@ -587,6 +588,7 @@ static void __init prefill_possible_map(void)
void __init setup_arch(char **cmdline_p)
{
cpu_probe();
+ unwind_init();

init_environ();
efi_init();
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index f623feb2129f..eaec82e02c92 100644
--- a/arch/loongarch/kernel/stacktrace.c
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -29,6 +29,7 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
regs->csr_era = thread_saved_ra(task);
}
regs->regs[1] = 0;
+ regs->regs[22] = 0;
}

for (unwind_start(&state, task, regs);
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index aebfc3733a76..f9f4eb00c92e 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -53,6 +53,32 @@

#include "access-helper.h"

+void *exception_table[EXCCODE_INT_START] = {
+ [0 ... EXCCODE_INT_START - 1] = handle_reserved,
+
+ [EXCCODE_TLBI] = handle_tlb_load,
+ [EXCCODE_TLBL] = handle_tlb_load,
+ [EXCCODE_TLBS] = handle_tlb_store,
+ [EXCCODE_TLBM] = handle_tlb_modify,
+ [EXCCODE_TLBNR] = handle_tlb_protect,
+ [EXCCODE_TLBNX] = handle_tlb_protect,
+ [EXCCODE_TLBPE] = handle_tlb_protect,
+ [EXCCODE_ADE] = handle_ade,
+ [EXCCODE_ALE] = handle_ale,
+ [EXCCODE_BCE] = handle_bce,
+ [EXCCODE_SYS] = handle_sys,
+ [EXCCODE_BP] = handle_bp,
+ [EXCCODE_INE] = handle_ri,
+ [EXCCODE_IPE] = handle_ri,
+ [EXCCODE_FPDIS] = handle_fpu,
+ [EXCCODE_LSXDIS] = handle_lsx,
+ [EXCCODE_LASXDIS] = handle_lasx,
+ [EXCCODE_FPE] = handle_fpe,
+ [EXCCODE_WATCH] = handle_watch,
+ [EXCCODE_BTDIS] = handle_lbt,
+};
+EXPORT_SYMBOL_GPL(exception_table);
+
static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
const char *loglvl, bool user)
{
@@ -1150,19 +1176,9 @@ void __init trap_init(void)
for (i = EXCCODE_INT_START; i <= EXCCODE_INT_END; i++)
set_handler(i * VECSIZE, handle_vint, VECSIZE);

- set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
- set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
- set_handler(EXCCODE_BCE * VECSIZE, handle_bce, VECSIZE);
- set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
- set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
- set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
- set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
- set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
- set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
- set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
- set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
- set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
- set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
+ /* Set exception vector handler */
+ for (i = EXCCODE_ADE; i <= EXCCODE_BTDIS; i++)
+ set_handler(i * VECSIZE, exception_table[i], VECSIZE);

cache_error_setup();

diff --git a/arch/loongarch/kernel/unwind_orc.c b/arch/loongarch/kernel/unwind_orc.c
new file mode 100644
index 000000000000..15f18d1e0dad
--- /dev/null
+++ b/arch/loongarch/kernel/unwind_orc.c
@@ -0,0 +1,516 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/objtool.h>
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/exception.h>
+#include <asm/orc_header.h>
+#include <asm/orc_lookup.h>
+#include <asm/orc_types.h>
+#include <asm/ptrace.h>
+#include <asm/setup.h>
+#include <asm/stacktrace.h>
+#include <asm/tlb.h>
+#include <asm/unwind.h>
+
+ORC_HEADER;
+
+#define orc_warn(fmt, ...) \
+ printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__)
+
+extern int __start_orc_unwind_ip[];
+extern int __stop_orc_unwind_ip[];
+extern struct orc_entry __start_orc_unwind[];
+extern struct orc_entry __stop_orc_unwind[];
+
+static bool orc_init __ro_after_init;
+static unsigned int lookup_num_blocks __ro_after_init;
+
+/* Fake frame pointer entry -- used as a fallback for generated code */
+static struct orc_entry orc_fp_entry = {
+ .sp_reg = ORC_REG_FP,
+ .sp_offset = 16,
+ .fp_reg = ORC_REG_PREV_SP,
+ .fp_offset = -16,
+ .ra_reg = ORC_REG_PREV_SP,
+ .ra_offset = -8,
+ .type = ORC_TYPE_CALL
+};
+
+/*
+ * If we crash with IP==0, the last successfully executed instruction
+ * was probably an indirect function call with a NULL function pointer,
+ * and we don't have unwind information for NULL.
+ * This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
+ * pointer into its parent and then continue normally from there.
+ */
+static struct orc_entry orc_null_entry = {
+ .sp_reg = ORC_REG_SP,
+ .sp_offset = sizeof(long),
+ .fp_reg = ORC_REG_UNDEFINED,
+ .type = ORC_TYPE_CALL
+};
+
+static inline unsigned long orc_ip(const int *ip)
+{
+ return (unsigned long)ip + *ip;
+}
+
+static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
+ unsigned int num_entries, unsigned long ip)
+{
+ int *first = ip_table;
+ int *mid = first, *found = first;
+ int *last = ip_table + num_entries - 1;
+
+ if (!num_entries)
+ return NULL;
+
+ /*
+ * Do a binary range search to find the rightmost duplicate of a given
+ * starting address. Some entries are section terminators which are
+ * "weak" entries for ensuring there are no gaps. They should be
+ * ignored when they conflict with a real entry.
+ */
+ while (first <= last) {
+ mid = first + ((last - first) / 2);
+
+ if (orc_ip(mid) <= ip) {
+ found = mid;
+ first = mid + 1;
+ } else
+ last = mid - 1;
+ }
+
+ return u_table + (found - ip_table);
+}
+
+#ifdef CONFIG_MODULES
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ struct module *mod;
+
+ mod = __module_address(ip);
+ if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
+ return NULL;
+
+ return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind, mod->arch.num_orcs, ip);
+}
+#else
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+ return NULL;
+}
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static struct orc_entry *orc_find(unsigned long ip);
+
+/*
+ * Ftrace dynamic trampolines do not have orc entries of their own.
+ * But they are copies of the ftrace entries that are static and
+ * defined in ftrace_*.S, which do have orc entries.
+ *
+ * If the unwinder comes across a ftrace trampoline, then find the
+ * ftrace function that was used to create it, and use that ftrace
+ * function's orc entry, as the placement of the return code in
+ * the stack will be identical.
+ */
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+ struct ftrace_ops *ops;
+ unsigned long tramp_addr, offset;
+
+ ops = ftrace_ops_trampoline(ip);
+ if (!ops)
+ return NULL;
+
+ /* Set tramp_addr to the start of the code copied by the trampoline */
+ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+ tramp_addr = (unsigned long)ftrace_regs_caller;
+ else
+ tramp_addr = (unsigned long)ftrace_caller;
+
+ /* Now place tramp_addr to the location within the trampoline ip is at */
+ offset = ip - ops->trampoline;
+ tramp_addr += offset;
+
+ /* Prevent unlikely recursion */
+ if (ip == tramp_addr)
+ return NULL;
+
+ return orc_find(tramp_addr);
+}
+#else
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+ return NULL;
+}
+#endif
+
+static struct orc_entry *orc_find(unsigned long ip)
+{
+ static struct orc_entry *orc;
+
+ if (ip == 0)
+ return &orc_null_entry;
+
+ /* For non-init vmlinux addresses, use the fast lookup table: */
+ if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
+ unsigned int idx, start, stop;
+
+ idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
+
+ if (unlikely((idx >= lookup_num_blocks-1))) {
+ orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
+ idx, lookup_num_blocks, (void *)ip);
+ return NULL;
+ }
+
+ start = orc_lookup[idx];
+ stop = orc_lookup[idx + 1] + 1;
+
+ if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
+ (__start_orc_unwind + stop > __stop_orc_unwind))) {
+ orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
+ idx, lookup_num_blocks, start, stop, (void *)ip);
+ return NULL;
+ }
+
+ return __orc_find(__start_orc_unwind_ip + start,
+ __start_orc_unwind + start, stop - start, ip);
+ }
+
+ /* vmlinux .init slow lookup: */
+ if (is_kernel_inittext(ip))
+ return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
+
+ /* Module lookup: */
+ orc = orc_module_find(ip);
+ if (orc)
+ return orc;
+
+ return orc_ftrace_find(ip);
+}
+
+#ifdef CONFIG_MODULES
+
+static DEFINE_MUTEX(sort_mutex);
+static int *cur_orc_ip_table = __start_orc_unwind_ip;
+static struct orc_entry *cur_orc_table = __start_orc_unwind;
+
+static void orc_sort_swap(void *_a, void *_b, int size)
+{
+ int delta = _b - _a;
+ int *a = _a, *b = _b, tmp;
+ struct orc_entry *orc_a, *orc_b;
+
+ /* Swap the .orc_unwind_ip entries: */
+ tmp = *a;
+ *a = *b + delta;
+ *b = tmp - delta;
+
+ /* Swap the corresponding .orc_unwind entries: */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+ orc_b = cur_orc_table + (b - cur_orc_ip_table);
+ swap(*orc_a, *orc_b);
+}
+
+static int orc_sort_cmp(const void *_a, const void *_b)
+{
+ const int *a = _a, *b = _b;
+ unsigned long a_val = orc_ip(a);
+ unsigned long b_val = orc_ip(b);
+ struct orc_entry *orc_a;
+
+ if (a_val > b_val)
+ return 1;
+ if (a_val < b_val)
+ return -1;
+
+ /*
+ * The "weak" section terminator entries need to always be first
+ * to ensure the lookup code skips them in favor of real entries.
+ * These terminator entries exist to handle any gaps created by
+ * whitelisted .o files which didn't get objtool generation.
+ */
+ orc_a = cur_orc_table + (a - cur_orc_ip_table);
+
+ return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
+}
+
+void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
+ void *_orc, size_t orc_size)
+{
+ int *orc_ip = _orc_ip;
+ struct orc_entry *orc = _orc;
+ unsigned int num_entries = orc_ip_size / sizeof(int);
+
+ WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(*orc) != 0 ||
+ num_entries != orc_size / sizeof(*orc));
+
+ /*
+ * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
+ * associate an .orc_unwind_ip table entry with its corresponding
+ * .orc_unwind entry so they can both be swapped.
+ */
+ mutex_lock(&sort_mutex);
+ cur_orc_ip_table = orc_ip;
+ cur_orc_table = orc;
+ sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
+ mutex_unlock(&sort_mutex);
+
+ mod->arch.orc_unwind_ip = orc_ip;
+ mod->arch.orc_unwind = orc;
+ mod->arch.num_orcs = num_entries;
+}
+#endif
+
+void __init unwind_init(void)
+{
+ int i;
+ size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
+ size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
+ size_t num_entries = orc_ip_size / sizeof(int);
+ struct orc_entry *orc;
+
+ if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
+ orc_size % sizeof(struct orc_entry) != 0 ||
+ num_entries != orc_size / sizeof(struct orc_entry)) {
+ orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ /*
+ * Note, the orc_unwind and orc_unwind_ip tables were already
+ * sorted at build time via the 'sorttable' tool.
+ * It's ready for binary search straight away, no need to sort it.
+ */
+
+ /* Initialize the fast lookup table: */
+ lookup_num_blocks = orc_lookup_end - orc_lookup;
+ for (i = 0; i < lookup_num_blocks-1; i++) {
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+ num_entries, LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+
+ orc_lookup[i] = orc - __start_orc_unwind;
+ }
+
+ /* Initialize the ending block: */
+ orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries, LOOKUP_STOP_IP);
+ if (!orc) {
+ orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
+ return;
+ }
+ orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
+
+ orc_init = true;
+}
+
+static inline bool on_stack(struct stack_info *info, unsigned long addr, size_t len)
+{
+ unsigned long begin = info->begin;
+ unsigned long end = info->end;
+
+ return (info->type != STACK_TYPE_UNKNOWN &&
+ addr >= begin && addr < end && addr + len > begin && addr + len <= end);
+}
+
+static bool stack_access_ok(struct unwind_state *state, unsigned long addr, size_t len)
+{
+ struct stack_info *info = &state->stack_info;
+
+ if (on_stack(info, addr, len))
+ return true;
+
+ return !get_stack_info(addr, state->task, info) && on_stack(info, addr, len);
+}
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+ return __unwind_get_return_address(state);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+void unwind_start(struct unwind_state *state, struct task_struct *task,
+ struct pt_regs *regs)
+{
+ __unwind_start(state, task, regs);
+ state->type = UNWINDER_ORC;
+ if (!unwind_done(state) && !__kernel_text_address(state->pc))
+ unwind_next_frame(state);
+}
+EXPORT_SYMBOL_GPL(unwind_start);
+
+static bool is_entry_func(unsigned long addr)
+{
+ extern u32 kernel_entry;
+ extern u32 kernel_entry_end;
+
+ return addr >= (unsigned long)&kernel_entry && addr < (unsigned long)&kernel_entry_end;
+}
+
+static inline unsigned long bt_address(unsigned long ra)
+{
+ extern unsigned long eentry;
+
+ if (__kernel_text_address(ra))
+ return ra;
+
+ if (__module_text_address(ra))
+ return ra;
+
+ if (ra >= eentry && ra < eentry + EXCCODE_INT_END * VECSIZE) {
+ unsigned long func;
+ unsigned long type = (ra - eentry) / VECSIZE;
+ unsigned long offset = (ra - eentry) % VECSIZE;
+
+ switch (type) {
+ case 0 ... EXCCODE_INT_START - 1:
+ func = (unsigned long)exception_table[type];
+ break;
+ case EXCCODE_INT_START ... EXCCODE_INT_END:
+ func = (unsigned long)handle_vint;
+ break;
+ default:
+ func = (unsigned long)handle_reserved;
+ break;
+ }
+
+ return func + offset;
+ }
+
+ return ra;
+}
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+ unsigned long *p, pc;
+ struct pt_regs *regs;
+ struct orc_entry *orc;
+ struct stack_info *info = &state->stack_info;
+
+ if (unwind_done(state))
+ return false;
+
+ /* Don't let modules unload while we're reading their ORC data. */
+ preempt_disable();
+
+ if (is_entry_func(state->pc))
+ goto end;
+
+ orc = orc_find(state->pc);
+ if (!orc) {
+ orc = &orc_fp_entry;
+ state->error = true;
+ }
+
+ switch (orc->sp_reg) {
+ case ORC_REG_SP:
+ if (info->type == STACK_TYPE_IRQ && state->sp == info->end)
+ orc->type = ORC_TYPE_REGS;
+ else
+ state->sp = state->sp + orc->sp_offset;
+ break;
+ case ORC_REG_FP:
+ state->sp = state->fp;
+ break;
+ default:
+ orc_warn("unknown SP base reg %d at %pB\n", orc->sp_reg, (void *)state->pc);
+ goto err;
+ }
+
+ switch (orc->fp_reg) {
+ case ORC_REG_PREV_SP:
+ p = (unsigned long *)(state->sp + orc->fp_offset);
+ if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+ goto err;
+
+ state->fp = *p;
+ break;
+ case ORC_REG_UNDEFINED:
+ /* Nothing. */
+ break;
+ default:
+ orc_warn("unknown FP base reg %d at %pB\n", orc->fp_reg, (void *)state->pc);
+ goto err;
+ }
+
+ switch (orc->type) {
+ case ORC_TYPE_CALL:
+ if (orc->ra_reg == ORC_REG_PREV_SP) {
+ p = (unsigned long *)(state->sp + orc->ra_offset);
+ if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+ goto err;
+
+ pc = unwind_graph_addr(state, *p, state->sp);
+ pc -= LOONGARCH_INSN_SIZE;
+ } else if (orc->ra_reg == ORC_REG_UNDEFINED) {
+ if (!state->ra || state->ra == state->pc)
+ goto err;
+
+ pc = unwind_graph_addr(state, state->ra, state->sp);
+ pc -= LOONGARCH_INSN_SIZE;
+ state->ra = 0;
+ } else {
+ orc_warn("unknown ra base reg %d at %pB\n", orc->ra_reg, (void *)state->pc);
+ goto err;
+ }
+ break;
+ case ORC_TYPE_REGS:
+ if (info->type == STACK_TYPE_IRQ && state->sp == info->end)
+ regs = (struct pt_regs *)info->next_sp;
+ else
+ regs = (struct pt_regs *)state->sp;
+
+ if (!stack_access_ok(state, (unsigned long)regs, sizeof(*regs)))
+ goto err;
+
+ if ((info->end == (unsigned long)regs + sizeof(*regs)) &&
+ !regs->regs[3] && !regs->regs[1])
+ goto end;
+
+ if (user_mode(regs))
+ goto end;
+
+ pc = regs->csr_era;
+ if (!__kernel_text_address(pc))
+ goto err;
+
+ state->sp = regs->regs[3];
+ state->ra = regs->regs[1];
+ state->fp = regs->regs[22];
+ get_stack_info(state->sp, state->task, info);
+
+ break;
+ default:
+ orc_warn("unknown .orc_unwind entry type %d at %pB\n", orc->type, (void *)state->pc);
+ goto err;
+ }
+
+ state->pc = bt_address(pc);
+ if (!state->pc) {
+ pr_err("cannot find unwind pc at %pK\n", (void *)pc);
+ goto err;
+ }
+
+ if (!__kernel_text_address(state->pc))
+ goto err;
+
+ preempt_enable();
+ return true;
+
+err:
+ state->error = true;
+
+end:
+ preempt_enable();
+ state->stack_info.type = STACK_TYPE_UNKNOWN;
+ return false;
+}
+EXPORT_SYMBOL_GPL(unwind_next_frame);
diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S
index a5d0cd2035da..e8e97dbf9ca4 100644
--- a/arch/loongarch/kernel/vmlinux.lds.S
+++ b/arch/loongarch/kernel/vmlinux.lds.S
@@ -2,6 +2,7 @@
#include <linux/sizes.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
+#include <asm/orc_lookup.h>

#define PAGE_SIZE _PAGE_SIZE
#define RO_EXCEPTION_TABLE_ALIGN 4
@@ -122,6 +123,8 @@ SECTIONS
}
#endif

+ ORC_UNWIND_TABLE
+
.sdata : {
*(.sdata)
}
diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
index ba976509bfe8..1fcc4b7eda32 100644
--- a/arch/loongarch/kvm/switch.S
+++ b/arch/loongarch/kvm/switch.S
@@ -8,7 +8,7 @@
#include <asm/asmmacro.h>
#include <asm/loongarch.h>
#include <asm/regdef.h>
-#include <asm/stackframe.h>
+#include <asm/unwind_hints.h>

#define HGPR_OFFSET(x) (PT_R0 + 8*x)
#define GGPR_OFFSET(x) (KVM_ARCH_GGPR + 8*x)
@@ -112,6 +112,7 @@
.text
.cfi_sections .debug_frame
SYM_CODE_START(kvm_exc_entry)
+ UNWIND_HINT_UNDEFINED
csrwr a2, KVM_TEMP_KS
csrrd a2, KVM_VCPU_KS
addi.d a2, a2, KVM_VCPU_ARCH
@@ -279,3 +280,9 @@ SYM_FUNC_END(kvm_restore_lasx)
.section ".rodata"
SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
+
+#ifdef CONFIG_CPU_HAS_LBT
+STACK_FRAME_NON_STANDARD kvm_restore_fpu
+STACK_FRAME_NON_STANDARD kvm_restore_lsx
+STACK_FRAME_NON_STANDARD kvm_restore_lasx
+#endif
diff --git a/arch/loongarch/lib/clear_user.S b/arch/loongarch/lib/clear_user.S
index be741544e62b..72484e401318 100644
--- a/arch/loongarch/lib/clear_user.S
+++ b/arch/loongarch/lib/clear_user.S
@@ -10,6 +10,7 @@
#include <asm/asm-extable.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

SYM_FUNC_START(__clear_user)
/*
@@ -204,3 +205,4 @@ SYM_FUNC_START(__clear_user_fast)
_asm_extable 28b, .Lsmall_fixup
_asm_extable 29b, .Lexit
SYM_FUNC_END(__clear_user_fast)
+STACK_FRAME_NON_STANDARD __clear_user_fast
diff --git a/arch/loongarch/lib/copy_user.S b/arch/loongarch/lib/copy_user.S
index feec3d362803..d5279bba4700 100644
--- a/arch/loongarch/lib/copy_user.S
+++ b/arch/loongarch/lib/copy_user.S
@@ -10,6 +10,7 @@
#include <asm/asm-extable.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

SYM_FUNC_START(__copy_user)
/*
@@ -278,3 +279,4 @@ SYM_FUNC_START(__copy_user_fast)
_asm_extable 58b, .Lexit
_asm_extable 59b, .Lexit
SYM_FUNC_END(__copy_user_fast)
+STACK_FRAME_NON_STANDARD __copy_user_fast
diff --git a/arch/loongarch/lib/memcpy.S b/arch/loongarch/lib/memcpy.S
index fa1148878d2b..50f38320a312 100644
--- a/arch/loongarch/lib/memcpy.S
+++ b/arch/loongarch/lib/memcpy.S
@@ -9,6 +9,7 @@
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

.section .noinstr.text, "ax"

@@ -109,6 +110,7 @@ SYM_FUNC_START_NOALIGN(__memcpy_small)
jr ra
SYM_FUNC_END(__memcpy_small)
_ASM_NOKPROBE(__memcpy_small)
+STACK_FRAME_NON_STANDARD __memcpy_small

/*
* void *__memcpy_fast(void *dst, const void *src, size_t n)
diff --git a/arch/loongarch/lib/memset.S b/arch/loongarch/lib/memset.S
index 06d3ca54cbfe..c518fbec64db 100644
--- a/arch/loongarch/lib/memset.S
+++ b/arch/loongarch/lib/memset.S
@@ -9,6 +9,7 @@
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
+#include <asm/unwind_hints.h>

.macro fill_to_64 r0
bstrins.d \r0, \r0, 15, 8
@@ -166,3 +167,4 @@ SYM_FUNC_START(__memset_fast)
jr ra
SYM_FUNC_END(__memset_fast)
_ASM_NOKPROBE(__memset_fast)
+STACK_FRAME_NON_STANDARD __memset_fast
diff --git a/arch/loongarch/mm/tlb.c b/arch/loongarch/mm/tlb.c
index 0b95d32b30c9..5ac9beb5f093 100644
--- a/arch/loongarch/mm/tlb.c
+++ b/arch/loongarch/mm/tlb.c
@@ -9,8 +9,9 @@
#include <linux/hugetlb.h>
#include <linux/export.h>

-#include <asm/cpu.h>
#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/exception.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
@@ -266,24 +267,20 @@ static void setup_tlb_handler(int cpu)
setup_ptwalker();
local_flush_tlb_all();

+ if (cpu_has_ptw) {
+ exception_table[EXCCODE_TLBI] = handle_tlb_load_ptw;
+ exception_table[EXCCODE_TLBL] = handle_tlb_load_ptw;
+ exception_table[EXCCODE_TLBS] = handle_tlb_store_ptw;
+ exception_table[EXCCODE_TLBM] = handle_tlb_modify_ptw;
+ }
+
/* The tlb handlers are generated only once */
if (cpu == 0) {
memcpy((void *)tlbrentry, handle_tlb_refill, 0x80);
local_flush_icache_range(tlbrentry, tlbrentry + 0x80);
- if (!cpu_has_ptw) {
- set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load, VECSIZE);
- set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load, VECSIZE);
- set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store, VECSIZE);
- set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify, VECSIZE);
- } else {
- set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load_ptw, VECSIZE);
- set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load_ptw, VECSIZE);
- set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store_ptw, VECSIZE);
- set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify_ptw, VECSIZE);
- }
- set_handler(EXCCODE_TLBNR * VECSIZE, handle_tlb_protect, VECSIZE);
- set_handler(EXCCODE_TLBNX * VECSIZE, handle_tlb_protect, VECSIZE);
- set_handler(EXCCODE_TLBPE * VECSIZE, handle_tlb_protect, VECSIZE);
+
+ for (int i = EXCCODE_TLBL; i <= EXCCODE_TLBPE; i++)
+ set_handler(i * VECSIZE, exception_table[i], VECSIZE);
} else {
int vec_sz __maybe_unused;
void *addr __maybe_unused;
diff --git a/arch/loongarch/mm/tlbex.S b/arch/loongarch/mm/tlbex.S
index d5d682f3d29f..a44387b838af 100644
--- a/arch/loongarch/mm/tlbex.S
+++ b/arch/loongarch/mm/tlbex.S
@@ -18,6 +18,7 @@

.macro tlb_do_page_fault, write
SYM_CODE_START(tlb_do_page_fault_\write)
+ UNWIND_HINT_UNDEFINED
SAVE_ALL
csrrd a2, LOONGARCH_CSR_BADV
move a0, sp
@@ -32,6 +33,7 @@
tlb_do_page_fault 1

SYM_CODE_START(handle_tlb_protect)
+ UNWIND_HINT_UNDEFINED
BACKUP_T0T1
SAVE_ALL
move a0, sp
@@ -44,6 +46,7 @@ SYM_CODE_START(handle_tlb_protect)
SYM_CODE_END(handle_tlb_protect)

SYM_CODE_START(handle_tlb_load)
+ UNWIND_HINT_UNDEFINED
csrwr t0, EXCEPTION_KS0
csrwr t1, EXCEPTION_KS1
csrwr ra, EXCEPTION_KS2
@@ -190,6 +193,7 @@ nopage_tlb_load:
SYM_CODE_END(handle_tlb_load)

SYM_CODE_START(handle_tlb_load_ptw)
+ UNWIND_HINT_UNDEFINED
csrwr t0, LOONGARCH_CSR_KS0
csrwr t1, LOONGARCH_CSR_KS1
la_abs t0, tlb_do_page_fault_0
@@ -197,6 +201,7 @@ SYM_CODE_START(handle_tlb_load_ptw)
SYM_CODE_END(handle_tlb_load_ptw)

SYM_CODE_START(handle_tlb_store)
+ UNWIND_HINT_UNDEFINED
csrwr t0, EXCEPTION_KS0
csrwr t1, EXCEPTION_KS1
csrwr ra, EXCEPTION_KS2
@@ -346,6 +351,7 @@ nopage_tlb_store:
SYM_CODE_END(handle_tlb_store)

SYM_CODE_START(handle_tlb_store_ptw)
+ UNWIND_HINT_UNDEFINED
csrwr t0, LOONGARCH_CSR_KS0
csrwr t1, LOONGARCH_CSR_KS1
la_abs t0, tlb_do_page_fault_1
@@ -353,6 +359,7 @@ SYM_CODE_START(handle_tlb_store_ptw)
SYM_CODE_END(handle_tlb_store_ptw)

SYM_CODE_START(handle_tlb_modify)
+ UNWIND_HINT_UNDEFINED
csrwr t0, EXCEPTION_KS0
csrwr t1, EXCEPTION_KS1
csrwr ra, EXCEPTION_KS2
@@ -500,6 +507,7 @@ nopage_tlb_modify:
SYM_CODE_END(handle_tlb_modify)

SYM_CODE_START(handle_tlb_modify_ptw)
+ UNWIND_HINT_UNDEFINED
csrwr t0, LOONGARCH_CSR_KS0
csrwr t1, LOONGARCH_CSR_KS1
la_abs t0, tlb_do_page_fault_1
@@ -507,6 +515,7 @@ SYM_CODE_START(handle_tlb_modify_ptw)
SYM_CODE_END(handle_tlb_modify_ptw)

SYM_CODE_START(handle_tlb_refill)
+ UNWIND_HINT_UNDEFINED
csrwr t0, LOONGARCH_CSR_TLBRSAVE
csrrd t0, LOONGARCH_CSR_PGD
lddir t0, t0, 3
diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile
index c74c9921304f..7a4ad96522ac 100644
--- a/arch/loongarch/vdso/Makefile
+++ b/arch/loongarch/vdso/Makefile
@@ -3,6 +3,7 @@

KASAN_SANITIZE := n
KCOV_INSTRUMENT := n
+OBJECT_FILES_NON_STANDARD := y

# Include the generic Makefile to check the built vdso.
include $(srctree)/lib/vdso/Makefile
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index bb1339c7057b..39f2d4a05208 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -116,6 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
*/
#define __stringify_label(n) #n

+#define __annotate_reachable(c) ({ \
+ asm volatile(__stringify_label(c) ":\n\t" \
+ ".pushsection .discard.reachable\n\t" \
+ ".long " __stringify_label(c) "b - .\n\t" \
+ ".popsection\n\t"); \
+})
+#define annotate_reachable() __annotate_reachable(__COUNTER__)
+
#define __annotate_unreachable(c) ({ \
asm volatile(__stringify_label(c) ":\n\t" \
".pushsection .discard.unreachable\n\t" \
@@ -128,6 +136,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#define __annotate_jump_table __section(".rodata..c_jump_table")

#else /* !CONFIG_OBJTOOL */
+#define annotate_reachable()
#define annotate_unreachable()
#define __annotate_jump_table
#endif /* CONFIG_OBJTOOL */
diff --git a/scripts/Makefile b/scripts/Makefile
index 576cf64be667..e4cca53d2285 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -31,9 +31,12 @@ HOSTLDLIBS_sign-file = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null |

ifdef CONFIG_UNWINDER_ORC
ifeq ($(ARCH),x86_64)
-ARCH := x86
+SRCARCH := x86
endif
-HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/x86/include
+ifeq ($(ARCH),loongarch)
+SRCARCH := loongarch
+endif
+HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/$(SRCARCH)/include
HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
endif

--
2.42.0