[PATCH v4] powerpc/traps: Enhance readability for trap types

From: Xiongwei Song
Date: Fri Apr 09 2021 - 10:28:49 EST

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From: Xiongwei Song <sxwjean@xxxxxxxxx>

Create a new header named traps.h, define macros to list ppc interrupt
types in traps.h, replace the references of the trap hex values with these
macros.

Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S,
arch/powerpc/kernel/exceptions-64s.S and
arch/powerpc/include/asm/kvm_asm.h.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Xiongwei Song <sxwjean@xxxxxxxxx>
---

v3-v4:
Fix compile issue:
arch/powerpc/kernel/process.c:1473:14: error: 'INTERRUPT_MACHINE_CHECK' undeclared (first use in this function); did you mean 'TAINT_MACHINE_CHECK'?
I didn't add "Reported-by: kernel test robot <lkp@xxxxxxxxx>" here,
because it's improper for this patch.

v2-v3:
Correct the prefix of trap macros with INTERRUPT_, the previous prefix
is TRAP_, which is not precise. This is suggested by Segher Boessenkool
and Nicholas Piggin.

v1-v2:
Define more trap macros to replace more trap hexs in code, not just for
the __show_regs function. This is suggested by Christophe Leroy.

---
arch/powerpc/include/asm/interrupt.h | 9 +++++---
arch/powerpc/include/asm/ptrace.h | 3 ++-
arch/powerpc/include/asm/traps.h | 32 +++++++++++++++++++++++++++
arch/powerpc/kernel/interrupt.c | 3 ++-
arch/powerpc/kernel/process.c | 5 ++++-
arch/powerpc/mm/book3s64/hash_utils.c | 5 +++--
arch/powerpc/mm/fault.c | 21 +++++++++++-------
arch/powerpc/perf/core-book3s.c | 5 +++--
arch/powerpc/xmon/xmon.c | 16 +++++++++++---
9 files changed, 78 insertions(+), 21 deletions(-)
create mode 100644 arch/powerpc/include/asm/traps.h

diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 05e7fc4ffb50..4fd904fb5d59 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -8,6 +8,7 @@
#include <asm/ftrace.h>
#include <asm/kprobes.h>
#include <asm/runlatch.h>
+#include <asm/traps.h>

static inline void nap_adjust_return(struct pt_regs *regs)
{
@@ -70,7 +71,7 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
* CT_WARN_ON comes here via program_check_exception,
* so avoid recursion.
*/
- if (TRAP(regs) != 0x700)
+ if (TRAP(regs) != INTERRUPT_PROGRAM)
CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
}
#endif
@@ -175,7 +176,8 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte
/* Don't do any per-CPU operations until interrupt state is fixed */
#endif
/* Allow DEC and PMI to be traced when they are soft-NMI */
- if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260) {
+ if (TRAP(regs) != INTERRUPT_DECREMENTER &&
+ TRAP(regs) != INTERRUPT_PERFMON) {
state->ftrace_enabled = this_cpu_get_ftrace_enabled();
this_cpu_set_ftrace_enabled(0);
}
@@ -204,7 +206,8 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter
*/

#ifdef CONFIG_PPC64
- if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260)
+ if (TRAP(regs) != INTERRUPT_DECREMENTER &&
+ TRAP(regs) != INTERRUPT_PERFMON)
this_cpu_set_ftrace_enabled(state->ftrace_enabled);

#ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 95600f3a6523..07ff8629e776 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -21,6 +21,7 @@

#include <uapi/asm/ptrace.h>
#include <asm/asm-const.h>
+#include <asm/traps.h>

#ifndef __ASSEMBLY__
struct pt_regs
@@ -237,7 +238,7 @@ static inline bool trap_is_unsupported_scv(struct pt_regs *regs)

static inline bool trap_is_syscall(struct pt_regs *regs)
{
- return (trap_is_scv(regs) || TRAP(regs) == 0xc00);
+ return (trap_is_scv(regs) || TRAP(regs) == INTERRUPT_SYSCALL);
}

static inline bool trap_norestart(struct pt_regs *regs)
diff --git a/arch/powerpc/include/asm/traps.h b/arch/powerpc/include/asm/traps.h
new file mode 100644
index 000000000000..2e64e10afcef
--- /dev/null
+++ b/arch/powerpc/include/asm/traps.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_PPC_TRAPS_H
+#define _ASM_PPC_TRAPS_H
+
+#if defined(CONFIG_BOOKE) || defined(CONFIG_4xx)
+#define INTERRUPT_MACHINE_CHECK 0x000
+#define INTERRUPT_CRITICAL_INPUT 0x100
+#define INTERRUPT_ALTIVEC_UNAVAIL 0x200
+#define INTERRUPT_PERFMON 0x260
+#define INTERRUPT_DOORBELL 0x280
+#define INTERRUPT_DEBUG 0xd00
+#else
+#define INTERRUPT_SYSTEM_RESET 0x100
+#define INTERRUPT_MACHINE_CHECK 0x200
+#define INTERRUPT_DATA_SEGMENT 0x380
+#define INTERRUPT_INST_SEGMENT 0x480
+#define INTERRUPT_DOORBELL 0xa00
+#define INTERRUPT_TRACE 0xd00
+#define INTERRUPT_H_DATA_STORAGE 0xe00
+#define INTERRUPT_PERFMON 0xf00
+#define INTERRUPT_H_FAC_UNAVAIL 0xf80
+#endif
+
+#define INTERRUPT_DATA_STORAGE 0x300
+#define INTERRUPT_INST_STORAGE 0x400
+#define INTERRUPT_ALIGNMENT 0x600
+#define INTERRUPT_PROGRAM 0x700
+#define INTERRUPT_FP_UNAVAIL 0x800
+#define INTERRUPT_DECREMENTER 0x900
+#define INTERRUPT_SYSCALL 0xc00
+
+#endif /* _ASM_PPC_TRAPS_H */
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index c4dd4b8f9cfa..72689f7ca7c8 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -19,6 +19,7 @@
#include <asm/syscall.h>
#include <asm/time.h>
#include <asm/unistd.h>
+#include <asm/traps.h>

#if defined(CONFIG_PPC_ADV_DEBUG_REGS) && defined(CONFIG_PPC32)
unsigned long global_dbcr0[NR_CPUS];
@@ -456,7 +457,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
* CT_WARN_ON comes here via program_check_exception,
* so avoid recursion.
*/
- if (TRAP(regs) != 0x700)
+ if (TRAP(regs) != INTERRUPT_PROGRAM)
CT_WARN_ON(ct_state() == CONTEXT_USER);

kuap = kuap_get_and_assert_locked();
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index b966c8e0cead..92cd49427b2f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -64,6 +64,7 @@
#include <asm/asm-prototypes.h>
#include <asm/stacktrace.h>
#include <asm/hw_breakpoint.h>
+#include <asm/traps.h>

#include <linux/kprobes.h>
#include <linux/kdebug.h>
@@ -1469,7 +1470,9 @@ static void __show_regs(struct pt_regs *regs)
trap = TRAP(regs);
if (!trap_is_syscall(regs) && cpu_has_feature(CPU_FTR_CFAR))
pr_cont("CFAR: "REG" ", regs->orig_gpr3);
- if (trap == 0x200 || trap == 0x300 || trap == 0x600) {
+ if (trap == INTERRUPT_MACHINE_CHECK ||
+ trap == INTERRUPT_DATA_STORAGE ||
+ trap == INTERRUPT_ALIGNMENT) {
if (IS_ENABLED(CONFIG_4xx) || IS_ENABLED(CONFIG_BOOKE))
pr_cont("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
else
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 7719995323c3..2bf06e01b309 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -64,6 +64,7 @@
#include <asm/pte-walk.h>
#include <asm/asm-prototypes.h>
#include <asm/ultravisor.h>
+#include <asm/traps.h>

#include <mm/mmu_decl.h>

@@ -1145,7 +1146,7 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)

/* page is dirty */
if (!test_bit(PG_dcache_clean, &page->flags) && !PageReserved(page)) {
- if (trap == 0x400) {
+ if (trap == INTERRUPT_INST_STORAGE) {
flush_dcache_icache_page(page);
set_bit(PG_dcache_clean, &page->flags);
} else
@@ -1545,7 +1546,7 @@ DEFINE_INTERRUPT_HANDLER_RET(__do_hash_fault)
if (user_mode(regs) || (region_id == USER_REGION_ID))
access &= ~_PAGE_PRIVILEGED;

- if (TRAP(regs) == 0x400)
+ if (TRAP(regs) == INTERRUPT_INST_STORAGE)
access |= _PAGE_EXEC;

err = hash_page_mm(mm, ea, access, TRAP(regs), flags);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 0c0b1c2cfb49..1215fa2a72a7 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -44,6 +44,7 @@
#include <asm/debug.h>
#include <asm/kup.h>
#include <asm/inst.h>
+#include <asm/traps.h>

/*
@@ -197,7 +198,7 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr,
static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code,
unsigned long address, bool is_write)
{
- int is_exec = TRAP(regs) == 0x400;
+ int is_exec = TRAP(regs) == INTERRUPT_INST_STORAGE;

/* NX faults set DSISR_PROTFAULT on the 8xx, DSISR_NOEXEC_OR_G on others */
if (is_exec && (error_code & (DSISR_NOEXEC_OR_G | DSISR_KEYFAULT |
@@ -391,7 +392,7 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
struct vm_area_struct * vma;
struct mm_struct *mm = current->mm;
unsigned int flags = FAULT_FLAG_DEFAULT;
- int is_exec = TRAP(regs) == 0x400;
+ int is_exec = TRAP(regs) == INTERRUPT_INST_STORAGE;
int is_user = user_mode(regs);
int is_write = page_fault_is_write(error_code);
vm_fault_t fault, major = 0;
@@ -588,20 +589,24 @@ void __bad_page_fault(struct pt_regs *regs, int sig)
/* kernel has accessed a bad area */

switch (TRAP(regs)) {
- case 0x300:
- case 0x380:
- case 0xe00:
+ case INTERRUPT_DATA_STORAGE:
+#if !defined(CONFIG_BOOKE) && !defined(CONFIG_4xx)
+ case INTERRUPT_DATA_SEGMENT:
+ case INTERRUPT_H_DATA_STORAGE:
+#endif
pr_alert("BUG: %s on %s at 0x%08lx\n",
regs->dar < PAGE_SIZE ? "Kernel NULL pointer dereference" :
"Unable to handle kernel data access",
is_write ? "write" : "read", regs->dar);
break;
- case 0x400:
- case 0x480:
+ case INTERRUPT_INST_STORAGE:
+#if !defined(CONFIG_BOOKE) && !defined(CONFIG_4xx)
+ case INTERRUPT_INST_SEGMENT:
+#endif
pr_alert("BUG: Unable to handle kernel instruction fetch%s",
regs->nip < PAGE_SIZE ? " (NULL pointer?)\n" : "\n");
break;
- case 0x600:
+ case INTERRUPT_ALIGNMENT:
pr_alert("BUG: Unable to handle kernel unaligned access at 0x%08lx\n",
regs->dar);
break;
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 766f064f00fb..6e34f5bba232 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -17,6 +17,7 @@
#include <asm/firmware.h>
#include <asm/ptrace.h>
#include <asm/code-patching.h>
+#include <asm/traps.h>

#ifdef CONFIG_PPC64
#include "internal.h"
@@ -168,7 +169,7 @@ static bool regs_use_siar(struct pt_regs *regs)
* they have not been setup using perf_read_regs() and so regs->result
* is something random.
*/
- return ((TRAP(regs) == 0xf00) && regs->result);
+ return ((TRAP(regs) == INTERRUPT_PERFMON) && regs->result);
}

/*
@@ -347,7 +348,7 @@ static inline void perf_read_regs(struct pt_regs *regs)
* hypervisor samples as well as samples in the kernel with
* interrupts off hence the userspace check.
*/
- if (TRAP(regs) != 0xf00)
+ if (TRAP(regs) != INTERRUPT_PERFMON)
use_siar = 0;
else if ((ppmu->flags & PPMU_NO_SIAR))
use_siar = 0;
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 3fe37495f63d..59136634c5ce 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -54,6 +54,7 @@
#include <asm/code-patching.h>
#include <asm/sections.h>
#include <asm/inst.h>
+#include <asm/traps.h>

#ifdef CONFIG_PPC64
#include <asm/hvcall.h>
@@ -1769,7 +1770,12 @@ static void excprint(struct pt_regs *fp)
printf(" sp: %lx\n", fp->gpr[1]);
printf(" msr: %lx\n", fp->msr);

- if (trap == 0x300 || trap == 0x380 || trap == 0x600 || trap == 0x200) {
+ if (trap == INTERRUPT_DATA_STORAGE ||
+#if !defined(CONFIG_BOOKE) && !defined(CONFIG_4xx)
+ trap == INTERRUPT_DATA_SEGMENT ||
+#endif
+ trap == INTERRUPT_ALIGNMENT ||
+ trap == INTERRUPT_MACHINE_CHECK) {
printf(" dar: %lx\n", fp->dar);
if (trap != 0x380)
printf(" dsisr: %lx\n", fp->dsisr);
@@ -1785,7 +1791,7 @@ static void excprint(struct pt_regs *fp)
current->pid, current->comm);
}

- if (trap == 0x700)
+ if (trap == INTERRUPT_PROGRAM)
print_bug_trap(fp);

printf(linux_banner);
@@ -1846,7 +1852,11 @@ static void prregs(struct pt_regs *fp)
printf("ctr = "REG" xer = "REG" trap = %4lx\n",
fp->ctr, fp->xer, fp->trap);
trap = TRAP(fp);
- if (trap == 0x300 || trap == 0x380 || trap == 0x600)
+ if (trap == INTERRUPT_DATA_STORAGE ||
+#if !defined(CONFIG_BOOKE) && !defined(CONFIG_4xx)
+ trap == INTERRUPT_DATA_SEGMENT ||
+#endif
+ trap == INTERRUPT_ALIGNMENT)
printf("dar = "REG" dsisr = %.8lx\n", fp->dar, fp->dsisr);
}

--
2.17.1

Next message: Mark Rutland: "Re: [PATCH v3] arm64: mte: Move MTE TCF0 check in entry-common"
Previous message: Brian Foster: "Re: [PATCH] xfs: fix return of uninitialized value in variable error"
Next in thread: Nicholas Piggin: "Re: [PATCH v4] powerpc/traps: Enhance readability for trap types"
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