[PATCH 20/29] csky: Reconstruct VDSO framework

From: guoren
Date: Thu Jan 21 2021 - 02:12:09 EST

Next message: guoren: "[PATCH 17/29] csky: Fixup do_page_fault parent irq status"
Previous message: guoren: "[PATCH 25/29] csky: Fixup swapon"
In reply to: guoren: "[PATCH 25/29] csky: Fixup swapon"
Next in thread: guoren: "[PATCH 17/29] csky: Fixup do_page_fault parent irq status"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

Reconstruct vdso framework to support future vsyscall,
vgettimeofday features. These are very important features to reduce
system calls into the kernel for performance improvement.

The patch is reference RISC-V's

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
---
arch/csky/abiv1/inc/abi/vdso.h | 18 ++--
arch/csky/abiv2/inc/abi/vdso.h | 20 +----
arch/csky/include/asm/vdso.h | 19 ++++-
arch/csky/kernel/Makefile | 2 +-
arch/csky/kernel/signal.c | 4 +-
arch/csky/kernel/vdso.c | 123 +++++++++++++++------------
arch/csky/kernel/vdso/.gitignore | 4 +
arch/csky/kernel/vdso/Makefile | 67 +++++++++++++++
arch/csky/kernel/vdso/note.S | 12 +++
arch/csky/kernel/vdso/rt_sigreturn.S | 14 +++
arch/csky/kernel/vdso/so2s.sh | 5 ++
arch/csky/kernel/vdso/vdso.S | 16 ++++
arch/csky/kernel/vdso/vdso.lds.S | 54 ++++++++++++
13 files changed, 269 insertions(+), 89 deletions(-)
create mode 100644 arch/csky/kernel/vdso/.gitignore
create mode 100644 arch/csky/kernel/vdso/Makefile
create mode 100644 arch/csky/kernel/vdso/note.S
create mode 100644 arch/csky/kernel/vdso/rt_sigreturn.S
create mode 100755 arch/csky/kernel/vdso/so2s.sh
create mode 100644 arch/csky/kernel/vdso/vdso.S
create mode 100644 arch/csky/kernel/vdso/vdso.lds.S

diff --git a/arch/csky/abiv1/inc/abi/vdso.h b/arch/csky/abiv1/inc/abi/vdso.h
index 14352f524f1d..9e6d0a2fdd2b 100644
--- a/arch/csky/abiv1/inc/abi/vdso.h
+++ b/arch/csky/abiv1/inc/abi/vdso.h
@@ -1,17 +1,9 @@
/* SPDX-License-Identifier: GPL-2.0 */

-#include <linux/uaccess.h>
+#ifndef __ABI_CSKY_VDSO_H
+#define __ABI_CSKY_VDSO_H

-static inline int setup_vdso_page(unsigned short *ptr)
-{
- int err = 0;
+/* movi r1, 127; addi r1, (139 - 127) */
+#define SET_SYSCALL_ID .long 0x20b167f1

- /* movi r1, 127 */
- err |= __put_user(0x67f1, ptr + 0);
- /* addi r1, (139 - 127) */
- err |= __put_user(0x20b1, ptr + 1);
- /* trap 0 */
- err |= __put_user(0x0008, ptr + 2);
-
- return err;
-}
+#endif /* __ABI_CSKY_VDSO_H */
diff --git a/arch/csky/abiv2/inc/abi/vdso.h b/arch/csky/abiv2/inc/abi/vdso.h
index b60d4a070326..40fd10d893ff 100644
--- a/arch/csky/abiv2/inc/abi/vdso.h
+++ b/arch/csky/abiv2/inc/abi/vdso.h
@@ -3,21 +3,7 @@
#ifndef __ABI_CSKY_VDSO_H
#define __ABI_CSKY_VDSO_H

-#include <linux/uaccess.h>
+/* movi r7, 173 */
+#define SET_SYSCALL_ID .long 0x008bea07

-static inline int setup_vdso_page(unsigned short *ptr)
-{
- int err = 0;
-
- /* movi r7, 173 */
- err |= __put_user(0xea07, ptr);
- err |= __put_user(0x008b, ptr+1);
-
- /* trap 0 */
- err |= __put_user(0xc000, ptr+2);
- err |= __put_user(0x2020, ptr+3);
-
- return err;
-}
-
-#endif /* __ABI_CSKY_STRING_H */
+#endif /* __ABI_CSKY_VDSO_H */
diff --git a/arch/csky/include/asm/vdso.h b/arch/csky/include/asm/vdso.h
index d963d691f3a1..12c5d638e784 100644
--- a/arch/csky/include/asm/vdso.h
+++ b/arch/csky/include/asm/vdso.h
@@ -3,10 +3,23 @@
#ifndef __ASM_CSKY_VDSO_H
#define __ASM_CSKY_VDSO_H

-#include <abi/vdso.h>
+#include <linux/types.h>

-struct csky_vdso {
- unsigned short rt_signal_retcode[4];
+struct vdso_data {
};

+/*
+ * The VDSO symbols are mapped into Linux so we can just use regular symbol
+ * addressing to get their offsets in userspace. The symbols are mapped at an
+ * offset of 0, but since the linker must support setting weak undefined
+ * symbols to the absolute address 0 it also happens to support other low
+ * addresses even when the code model suggests those low addresses would not
+ * otherwise be availiable.
+ */
+#define VDSO_SYMBOL(base, name) \
+({ \
+ extern const char __vdso_##name[]; \
+ (void __user *)((unsigned long)(base) + __vdso_##name); \
+})
+
#endif /* __ASM_CSKY_VDSO_H */
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 37f37c0e934a..6c0f36010ed0 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
extra-y := head.o vmlinux.lds

-obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o
+obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
obj-y += power.o syscall.o syscall_table.o setup.o
obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
obj-y += probes/
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 37ea64ed3c12..312f046d452d 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -134,7 +134,6 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
- struct csky_vdso *vdso = current->mm->context.vdso;

frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
@@ -152,7 +151,8 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
return -EFAULT;

/* Set up to return from userspace. */
- regs->lr = (unsigned long)(vdso->rt_signal_retcode);
+ regs->lr = (unsigned long)VDSO_SYMBOL(
+ current->mm->context.vdso, rt_sigreturn);

/*
* Set up registers for signal handler.
diff --git a/arch/csky/kernel/vdso.c b/arch/csky/kernel/vdso.c
index abc3dbc658d4..839523920843 100644
--- a/arch/csky/kernel/vdso.c
+++ b/arch/csky/kernel/vdso.c
@@ -1,86 +1,103 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

-#include <linux/kernel.h>
-#include <linux/err.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/init.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
-#include <linux/vmalloc.h>
-#include <linux/unistd.h>
-#include <linux/uaccess.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/slab.h>

+#include <asm/page.h>
#include <asm/vdso.h>
-#include <asm/cacheflush.h>

-static struct page *vdso_page;
+extern char vdso_start[], vdso_end[];

-static int __init init_vdso(void)
-{
- struct csky_vdso *vdso;
- int err = 0;
-
- vdso_page = alloc_page(GFP_KERNEL);
- if (!vdso_page)
- panic("Cannot allocate vdso");
+static unsigned int vdso_pages;
+static struct page **vdso_pagelist;

- vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
- if (!vdso)
- panic("Cannot map vdso");
+/*
+ * The vDSO data page.
+ */
+static union {
+ struct vdso_data data;
+ u8 page[PAGE_SIZE];
+} vdso_data_store __page_aligned_data;
+struct vdso_data *vdso_data = &vdso_data_store.data;

- clear_page(vdso);
-
- err = setup_vdso_page(vdso->rt_signal_retcode);
- if (err)
- panic("Cannot set signal return code, err: %x.", err);
+static int __init vdso_init(void)
+{
+ unsigned int i;
+
+ vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
+ vdso_pagelist =
+ kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
+ if (unlikely(vdso_pagelist == NULL)) {
+ pr_err("vdso: pagelist allocation failed\n");
+ return -ENOMEM;
+ }

- dcache_wb_range((unsigned long)vdso, (unsigned long)vdso + 16);
+ for (i = 0; i < vdso_pages; i++) {
+ struct page *pg;

- vunmap(vdso);
+ pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
+ vdso_pagelist[i] = pg;
+ }
+ vdso_pagelist[i] = virt_to_page(vdso_data);

return 0;
}
-subsys_initcall(init_vdso);
+arch_initcall(vdso_init);

-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp)
{
- int ret;
- unsigned long addr;
struct mm_struct *mm = current->mm;
+ unsigned long vdso_base, vdso_len;
+ int ret;

- mmap_write_lock(mm);
+ vdso_len = (vdso_pages + 1) << PAGE_SHIFT;

- addr = get_unmapped_area(NULL, STACK_TOP, PAGE_SIZE, 0, 0);
- if (IS_ERR_VALUE(addr)) {
- ret = addr;
- goto up_fail;
+ mmap_write_lock(mm);
+ vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
+ if (IS_ERR_VALUE(vdso_base)) {
+ ret = vdso_base;
+ goto end;
}

- ret = install_special_mapping(
- mm,
- addr,
- PAGE_SIZE,
- VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
- &vdso_page);
- if (ret)
- goto up_fail;
+ /*
+ * Put vDSO base into mm struct. We need to do this before calling
+ * install_special_mapping or the perf counter mmap tracking code
+ * will fail to recognise it as a vDSO (since arch_vma_name fails).
+ */
+ mm->context.vdso = (void *)vdso_base;
+
+ ret =
+ install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
+ (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
+ vdso_pagelist);
+
+ if (unlikely(ret)) {
+ mm->context.vdso = NULL;
+ goto end;
+ }

- mm->context.vdso = (void *)addr;
+ vdso_base += (vdso_pages << PAGE_SHIFT);
+ ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
+ (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]);

-up_fail:
+ if (unlikely(ret))
+ mm->context.vdso = NULL;
+end:
mmap_write_unlock(mm);
return ret;
}

const char *arch_vma_name(struct vm_area_struct *vma)
{
- if (vma->vm_mm == NULL)
- return NULL;
-
- if (vma->vm_start == (long)vma->vm_mm->context.vdso)
+ if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
return "[vdso]";
- else
- return NULL;
+ if (vma->vm_mm && (vma->vm_start ==
+ (long)vma->vm_mm->context.vdso + PAGE_SIZE))
+ return "[vdso_data]";
+ return NULL;
}
diff --git a/arch/csky/kernel/vdso/.gitignore b/arch/csky/kernel/vdso/.gitignore
new file mode 100644
index 000000000000..3a19def868ec
--- /dev/null
+++ b/arch/csky/kernel/vdso/.gitignore
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+vdso.lds
+*.tmp
+vdso-syms.S
diff --git a/arch/csky/kernel/vdso/Makefile b/arch/csky/kernel/vdso/Makefile
new file mode 100644
index 000000000000..13ac549c6587
--- /dev/null
+++ b/arch/csky/kernel/vdso/Makefile
@@ -0,0 +1,67 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
+# the inclusion of generic Makefile.
+ARCH_REL_TYPE_ABS := R_CKCORE_ADDR32|R_CKCORE_JUMP_SLOT
+include $(srctree)/lib/vdso/Makefile
+
+# Symbols present in the vdso
+vdso-syms = rt_sigreturn
+
+# Files to link into the vdso
+obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o
+
+ccflags-y := -fno-stack-protector
+
+# Build rules
+targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds vdso-dummy.o
+obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
+
+obj-y += vdso.o vdso-syms.o
+CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
+
+# Disable gcov profiling for VDSO code
+GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
+
+# Force dependency
+$(obj)/vdso.o: $(obj)/vdso.so
+
+SYSCFLAGS_vdso.so.dbg = $(c_flags)
+$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) FORCE
+ $(call if_changed,vdsold)
+SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
+ -Wl,--build-id=sha1 -Wl,--hash-style=both
+
+$(obj)/vdso-syms.S: $(obj)/vdso.so FORCE
+ $(call if_changed,so2s)
+
+# strip rule for the .so file
+$(obj)/%.so: OBJCOPYFLAGS := -S
+$(obj)/%.so: $(obj)/%.so.dbg FORCE
+ $(call if_changed,objcopy)
+
+# actual build commands
+# The DSO images are built using a special linker script
+# Make sure only to export the intended __vdso_xxx symbol offsets.
+quiet_cmd_vdsold = VDSOLD $@
+ cmd_vdsold = $(CC) $(KBUILD_CFLAGS) $(call cc-option, -no-pie) -nostdlib -nostartfiles $(SYSCFLAGS_$(@F)) \
+ -Wl,-T,$(filter-out FORCE,$^) -o $@.tmp && \
+ $(CROSS_COMPILE)objcopy \
+ $(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@ && \
+ rm $@.tmp
+
+# Extracts symbol offsets from the VDSO, converting them into an assembly file
+# that contains the same symbols at the same offsets.
+quiet_cmd_so2s = SO2S $@
+ cmd_so2s = $(NM) -D $< | $(srctree)/$(src)/so2s.sh > $@
+
+# install commands for the unstripped file
+quiet_cmd_vdso_install = INSTALL $@
+ cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@
+
+vdso.so: $(obj)/vdso.so.dbg
+ @mkdir -p $(MODLIB)/vdso
+ $(call cmd,vdso_install)
+
+vdso_install: vdso.so
diff --git a/arch/csky/kernel/vdso/note.S b/arch/csky/kernel/vdso/note.S
new file mode 100644
index 000000000000..2a956c942211
--- /dev/null
+++ b/arch/csky/kernel/vdso/note.S
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
+ * Here we can supply some information useful to userland.
+ */
+
+#include <linux/elfnote.h>
+#include <linux/version.h>
+
+ELFNOTE_START(Linux, 0, "a")
+ .long LINUX_VERSION_CODE
+ELFNOTE_END
diff --git a/arch/csky/kernel/vdso/rt_sigreturn.S b/arch/csky/kernel/vdso/rt_sigreturn.S
new file mode 100644
index 000000000000..0a6bd1216118
--- /dev/null
+++ b/arch/csky/kernel/vdso/rt_sigreturn.S
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/linkage.h>
+#include <asm/unistd.h>
+#include <abi/vdso.h>
+
+ .text
+ENTRY(__vdso_rt_sigreturn)
+ .cfi_startproc
+ .cfi_signal_frame
+ SET_SYSCALL_ID
+ trap 0
+ .cfi_endproc
+ENDPROC(__vdso_rt_sigreturn)
diff --git a/arch/csky/kernel/vdso/so2s.sh b/arch/csky/kernel/vdso/so2s.sh
new file mode 100755
index 000000000000..69da3d529c6d
--- /dev/null
+++ b/arch/csky/kernel/vdso/so2s.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+
+sed 's!$[0-9a-f]*$ T $[a-z0-9_]*$$@@LINUX_5.10$*!.global \2\n.set \2,0x\1!' \
+| grep '^\.'
diff --git a/arch/csky/kernel/vdso/vdso.S b/arch/csky/kernel/vdso/vdso.S
new file mode 100644
index 000000000000..5162ca069494
--- /dev/null
+++ b/arch/csky/kernel/vdso/vdso.S
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+ __PAGE_ALIGNED_DATA
+
+ .globl vdso_start, vdso_end
+ .balign PAGE_SIZE
+vdso_start:
+ .incbin "arch/csky/kernel/vdso/vdso.so"
+ .balign PAGE_SIZE
+vdso_end:
+
+ .previous
diff --git a/arch/csky/kernel/vdso/vdso.lds.S b/arch/csky/kernel/vdso/vdso.lds.S
new file mode 100644
index 000000000000..8d226252d439
--- /dev/null
+++ b/arch/csky/kernel/vdso/vdso.lds.S
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <asm/page.h>
+
+OUTPUT_ARCH(csky)
+
+SECTIONS
+{
+ PROVIDE(_vdso_data = . + PAGE_SIZE);
+ . = SIZEOF_HEADERS;
+
+ .hash : { *(.hash) } :text
+ .gnu.hash : { *(.gnu.hash) }
+ .dynsym : { *(.dynsym) }
+ .dynstr : { *(.dynstr) }
+ .gnu.version : { *(.gnu.version) }
+ .gnu.version_d : { *(.gnu.version_d) }
+ .gnu.version_r : { *(.gnu.version_r) }
+
+ .note : { *(.note.*) } :text :note
+ .dynamic : { *(.dynamic) } :text :dynamic
+
+ .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
+ .eh_frame : { KEEP (*(.eh_frame)) } :text
+
+ .rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
+
+ . = 0x800;
+ .text : { *(.text .text.*) } :text
+
+ .data : {
+ *(.got.plt) *(.got)
+ *(.data .data.* .gnu.linkonce.d.*)
+ *(.dynbss)
+ *(.bss .bss.* .gnu.linkonce.b.*)
+ }
+}
+
+PHDRS
+{
+ text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
+ dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
+ note PT_NOTE FLAGS(4); /* PF_R */
+ eh_frame_hdr PT_GNU_EH_FRAME;
+}
+
+VERSION
+{
+ LINUX_5.10 {
+ global:
+ __vdso_rt_sigreturn;
+ local: *;
+ };
+}
--
2.17.1

Next message: guoren: "[PATCH 17/29] csky: Fixup do_page_fault parent irq status"
Previous message: guoren: "[PATCH 25/29] csky: Fixup swapon"
In reply to: guoren: "[PATCH 25/29] csky: Fixup swapon"
Next in thread: guoren: "[PATCH 17/29] csky: Fixup do_page_fault parent irq status"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]