[PATCH -next v9 5/5] arm64: support copy_mc_[user]_highpage()
From: Tong Tiangen
Date: Sun May 07 2023 - 21:45:26 EST
Currently, many scenarios that can tolerate memory errors when copying page
have been supported in the kernel[1][2][3], all of which are implemented by
copy_mc_[user]_highpage(). arm64 should also support this mechanism.
Due to mte, arm64 needs to have its own copy_mc_[user]_highpage()
architecture implementation, macros __HAVE_ARCH_COPY_MC_HIGHPAGE and
__HAVE_ARCH_COPY_MC_USER_HIGHPAGE have been added to control it.
Add new helper copy_mc_page() which provide a page copy implementation with
machine check safe. The copy_mc_page() in copy_mc_page.S is largely borrows
from copy_page() in copy_page.S and the main difference is copy_mc_page()
add extable entry to every load/store insn to support machine check safe.
Add new extable type EX_TYPE_COPY_MC_PAGE_ERR_ZERO which used in
copy_mc_page().
[1]a873dfe1032a ("mm, hwpoison: try to recover from copy-on write faults")
[2]5f2500b93cc9 ("mm/khugepaged: recover from poisoned anonymous memory")
[3]6b970599e807 ("mm: hwpoison: support recovery from ksm_might_need_to_copy()")
Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
---
arch/arm64/include/asm/asm-extable.h | 15 +++++
arch/arm64/include/asm/assembler.h | 4 ++
arch/arm64/include/asm/mte.h | 5 ++
arch/arm64/include/asm/page.h | 10 ++++
arch/arm64/lib/Makefile | 2 +
arch/arm64/lib/copy_mc_page.S | 89 ++++++++++++++++++++++++++++
arch/arm64/lib/mte.S | 27 +++++++++
arch/arm64/mm/copypage.c | 64 +++++++++++++++++---
arch/arm64/mm/extable.c | 7 ++-
include/linux/highmem.h | 4 ++
10 files changed, 217 insertions(+), 10 deletions(-)
create mode 100644 arch/arm64/lib/copy_mc_page.S
diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h
index 980d1dd8e1a3..819044fefbe7 100644
--- a/arch/arm64/include/asm/asm-extable.h
+++ b/arch/arm64/include/asm/asm-extable.h
@@ -10,6 +10,7 @@
#define EX_TYPE_UACCESS_ERR_ZERO 2
#define EX_TYPE_KACCESS_ERR_ZERO 3
#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
+#define EX_TYPE_COPY_MC_PAGE_ERR_ZERO 5
/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
#define EX_DATA_REG_ERR_SHIFT 0
@@ -51,6 +52,16 @@
#define _ASM_EXTABLE_UACCESS(insn, fixup) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
+#define _ASM_EXTABLE_COPY_MC_PAGE_ERR_ZERO(insn, fixup, err, zero) \
+ __ASM_EXTABLE_RAW(insn, fixup, \
+ EX_TYPE_COPY_MC_PAGE_ERR_ZERO, \
+ ( \
+ EX_DATA_REG(ERR, err) | \
+ EX_DATA_REG(ZERO, zero) \
+ ))
+
+#define _ASM_EXTABLE_COPY_MC_PAGE(insn, fixup) \
+ _ASM_EXTABLE_COPY_MC_PAGE_ERR_ZERO(insn, fixup, wzr, wzr)
/*
* Create an exception table entry for uaccess `insn`, which will branch to `fixup`
* when an unhandled fault is taken.
@@ -59,6 +70,10 @@
_ASM_EXTABLE_UACCESS(\insn, \fixup)
.endm
+ .macro _asm_extable_copy_mc_page, insn, fixup
+ _ASM_EXTABLE_COPY_MC_PAGE(\insn, \fixup)
+ .endm
+
/*
* Create an exception table entry for `insn` if `fixup` is provided. Otherwise
* do nothing.
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 376a980f2bad..547ab2f85888 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -154,6 +154,10 @@ lr .req x30 // link register
#define CPU_LE(code...) code
#endif
+#define CPY_MC(l, x...) \
+9999: x; \
+ _asm_extable_copy_mc_page 9999b, l
+
/*
* Define a macro that constructs a 64-bit value by concatenating two
* 32-bit registers. Note that on big endian systems the order of the
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
index c028afb1cd0b..df00d4aa226a 100644
--- a/arch/arm64/include/asm/mte.h
+++ b/arch/arm64/include/asm/mte.h
@@ -92,6 +92,7 @@ static inline bool try_page_mte_tagging(struct page *page)
void mte_zero_clear_page_tags(void *addr);
void mte_sync_tags(pte_t old_pte, pte_t pte);
void mte_copy_page_tags(void *kto, const void *kfrom);
+int mte_copy_mc_page_tags(void *kto, const void *kfrom);
void mte_thread_init_user(void);
void mte_thread_switch(struct task_struct *next);
void mte_cpu_setup(void);
@@ -128,6 +129,10 @@ static inline void mte_sync_tags(pte_t old_pte, pte_t pte)
static inline void mte_copy_page_tags(void *kto, const void *kfrom)
{
}
+static inline int mte_copy_mc_page_tags(void *kto, const void *kfrom)
+{
+ return 0;
+}
static inline void mte_thread_init_user(void)
{
}
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 2312e6ee595f..304cc86b8a10 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -29,6 +29,16 @@ void copy_user_highpage(struct page *to, struct page *from,
void copy_highpage(struct page *to, struct page *from);
#define __HAVE_ARCH_COPY_HIGHPAGE
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+int copy_mc_page(void *to, const void *from);
+int copy_mc_highpage(struct page *to, struct page *from);
+#define __HAVE_ARCH_COPY_MC_HIGHPAGE
+
+int copy_mc_user_highpage(struct page *to, struct page *from,
+ unsigned long vaddr, struct vm_area_struct *vma);
+#define __HAVE_ARCH_COPY_MC_USER_HIGHPAGE
+#endif
+
struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
unsigned long vaddr);
#define vma_alloc_zeroed_movable_folio vma_alloc_zeroed_movable_folio
diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index 29490be2546b..a2fd865b816d 100644
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -15,6 +15,8 @@ endif
lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o
+lib-$(CONFIG_ARCH_HAS_COPY_MC) += copy_mc_page.o
+
obj-$(CONFIG_CRC32) += crc32.o
obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/arm64/lib/copy_mc_page.S b/arch/arm64/lib/copy_mc_page.S
new file mode 100644
index 000000000000..656d831ef4b8
--- /dev/null
+++ b/arch/arm64/lib/copy_mc_page.S
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/assembler.h>
+#include <asm/page.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative.h>
+#include <asm/asm-extable.h>
+
+/*
+ * Copy a page from src to dest (both are page aligned) with machine check
+ *
+ * Parameters:
+ * x0 - dest
+ * x1 - src
+ * Returns:
+ * x0 - Return 0 if copy success, or -EFAULT if anything goes wrong
+ * while copying.
+ */
+SYM_FUNC_START(__pi_copy_mc_page)
+alternative_if ARM64_HAS_NO_HW_PREFETCH
+ // Prefetch three cache lines ahead.
+ prfm pldl1strm, [x1, #128]
+ prfm pldl1strm, [x1, #256]
+ prfm pldl1strm, [x1, #384]
+alternative_else_nop_endif
+
+CPY_MC(9998f, ldp x2, x3, [x1])
+CPY_MC(9998f, ldp x4, x5, [x1, #16])
+CPY_MC(9998f, ldp x6, x7, [x1, #32])
+CPY_MC(9998f, ldp x8, x9, [x1, #48])
+CPY_MC(9998f, ldp x10, x11, [x1, #64])
+CPY_MC(9998f, ldp x12, x13, [x1, #80])
+CPY_MC(9998f, ldp x14, x15, [x1, #96])
+CPY_MC(9998f, ldp x16, x17, [x1, #112])
+
+ add x0, x0, #256
+ add x1, x1, #128
+1:
+ tst x0, #(PAGE_SIZE - 1)
+
+alternative_if ARM64_HAS_NO_HW_PREFETCH
+ prfm pldl1strm, [x1, #384]
+alternative_else_nop_endif
+
+CPY_MC(9998f, stnp x2, x3, [x0, #-256])
+CPY_MC(9998f, ldp x2, x3, [x1])
+CPY_MC(9998f, stnp x4, x5, [x0, #16 - 256])
+CPY_MC(9998f, ldp x4, x5, [x1, #16])
+CPY_MC(9998f, stnp x6, x7, [x0, #32 - 256])
+CPY_MC(9998f, ldp x6, x7, [x1, #32])
+CPY_MC(9998f, stnp x8, x9, [x0, #48 - 256])
+CPY_MC(9998f, ldp x8, x9, [x1, #48])
+CPY_MC(9998f, stnp x10, x11, [x0, #64 - 256])
+CPY_MC(9998f, ldp x10, x11, [x1, #64])
+CPY_MC(9998f, stnp x12, x13, [x0, #80 - 256])
+CPY_MC(9998f, ldp x12, x13, [x1, #80])
+CPY_MC(9998f, stnp x14, x15, [x0, #96 - 256])
+CPY_MC(9998f, ldp x14, x15, [x1, #96])
+CPY_MC(9998f, stnp x16, x17, [x0, #112 - 256])
+CPY_MC(9998f, ldp x16, x17, [x1, #112])
+
+ add x0, x0, #128
+ add x1, x1, #128
+
+ b.ne 1b
+
+CPY_MC(9998f, stnp x2, x3, [x0, #-256])
+CPY_MC(9998f, stnp x4, x5, [x0, #16 - 256])
+CPY_MC(9998f, stnp x6, x7, [x0, #32 - 256])
+CPY_MC(9998f, stnp x8, x9, [x0, #48 - 256])
+CPY_MC(9998f, stnp x10, x11, [x0, #64 - 256])
+CPY_MC(9998f, stnp x12, x13, [x0, #80 - 256])
+CPY_MC(9998f, stnp x14, x15, [x0, #96 - 256])
+CPY_MC(9998f, stnp x16, x17, [x0, #112 - 256])
+
+ mov x0, #0
+ ret
+
+9998: mov x0, #-EFAULT
+ ret
+
+SYM_FUNC_END(__pi_copy_mc_page)
+SYM_FUNC_ALIAS(copy_mc_page, __pi_copy_mc_page)
+EXPORT_SYMBOL(copy_mc_page)
diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S
index 5018ac03b6bf..2b748e83f6cf 100644
--- a/arch/arm64/lib/mte.S
+++ b/arch/arm64/lib/mte.S
@@ -80,6 +80,33 @@ SYM_FUNC_START(mte_copy_page_tags)
ret
SYM_FUNC_END(mte_copy_page_tags)
+/*
+ * Copy the tags from the source page to the destination one wiht machine check safe
+ * x0 - address of the destination page
+ * x1 - address of the source page
+ * Returns:
+ * x0 - Return 0 if copy success, or
+ * -EFAULT if anything goes wrong while copying.
+ */
+SYM_FUNC_START(mte_copy_mc_page_tags)
+ mov x2, x0
+ mov x3, x1
+ multitag_transfer_size x5, x6
+1:
+CPY_MC(2f, ldgm x4, [x3])
+CPY_MC(2f, stgm x4, [x2])
+ add x2, x2, x5
+ add x3, x3, x5
+ tst x2, #(PAGE_SIZE - 1)
+ b.ne 1b
+
+ mov x0, #0
+ ret
+
+2: mov x0, #-EFAULT
+ ret
+SYM_FUNC_END(mte_copy_mc_page_tags)
+
/*
* Read tags from a user buffer (one tag per byte) and set the corresponding
* tags at the given kernel address. Used by PTRACE_POKEMTETAGS.
diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
index 4aadcfb01754..7cbc12ee6009 100644
--- a/arch/arm64/mm/copypage.c
+++ b/arch/arm64/mm/copypage.c
@@ -14,21 +14,34 @@
#include <asm/cpufeature.h>
#include <asm/mte.h>
-void copy_highpage(struct page *to, struct page *from)
+static int do_mte(struct page *to, struct page *from, void *kto, void *kfrom, bool mc)
{
- void *kto = page_address(to);
- void *kfrom = page_address(from);
-
- copy_page(kto, kfrom);
+ int ret = 0;
if (system_supports_mte() && page_mte_tagged(from)) {
if (kasan_hw_tags_enabled())
page_kasan_tag_reset(to);
/* It's a new page, shouldn't have been tagged yet */
WARN_ON_ONCE(!try_page_mte_tagging(to));
- mte_copy_page_tags(kto, kfrom);
- set_page_mte_tagged(to);
+ if (mc)
+ ret = mte_copy_mc_page_tags(kto, kfrom);
+ else
+ mte_copy_page_tags(kto, kfrom);
+
+ if (!ret)
+ set_page_mte_tagged(to);
}
+
+ return ret;
+}
+
+void copy_highpage(struct page *to, struct page *from)
+{
+ void *kto = page_address(to);
+ void *kfrom = page_address(from);
+
+ copy_page(kto, kfrom);
+ do_mte(to, from, kto, kfrom, false);
}
EXPORT_SYMBOL(copy_highpage);
@@ -39,3 +52,40 @@ void copy_user_highpage(struct page *to, struct page *from,
flush_dcache_page(to);
}
EXPORT_SYMBOL_GPL(copy_user_highpage);
+
+#ifdef CONFIG_ARCH_HAS_COPY_MC
+/*
+ * Return -EFAULT if anything goes wrong while copying page or mte.
+ */
+int copy_mc_highpage(struct page *to, struct page *from)
+{
+ void *kto = page_address(to);
+ void *kfrom = page_address(from);
+ int ret;
+
+ ret = copy_mc_page(kto, kfrom);
+ if (ret)
+ return -EFAULT;
+
+ ret = do_mte(to, from, kto, kfrom, true);
+ if (ret)
+ return -EFAULT;
+
+ return 0;
+}
+EXPORT_SYMBOL(copy_mc_highpage);
+
+int copy_mc_user_highpage(struct page *to, struct page *from,
+ unsigned long vaddr, struct vm_area_struct *vma)
+{
+ int ret;
+
+ ret = copy_mc_highpage(to, from);
+
+ if (!ret)
+ flush_dcache_page(to);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(copy_mc_user_highpage);
+#endif
diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c
index 28ec35e3d210..bdc81518d207 100644
--- a/arch/arm64/mm/extable.c
+++ b/arch/arm64/mm/extable.c
@@ -16,7 +16,7 @@ get_ex_fixup(const struct exception_table_entry *ex)
return ((unsigned long)&ex->fixup + ex->fixup);
}
-static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
+static bool ex_handler_fixup_err_zero(const struct exception_table_entry *ex,
struct pt_regs *regs)
{
int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
@@ -69,7 +69,7 @@ bool fixup_exception(struct pt_regs *regs)
return ex_handler_bpf(ex, regs);
case EX_TYPE_UACCESS_ERR_ZERO:
case EX_TYPE_KACCESS_ERR_ZERO:
- return ex_handler_uaccess_err_zero(ex, regs);
+ return ex_handler_fixup_err_zero(ex, regs);
case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
return ex_handler_load_unaligned_zeropad(ex, regs);
}
@@ -87,7 +87,8 @@ bool fixup_exception_mc(struct pt_regs *regs)
switch (ex->type) {
case EX_TYPE_UACCESS_ERR_ZERO:
- return ex_handler_uaccess_err_zero(ex, regs);
+ case EX_TYPE_COPY_MC_PAGE_ERR_ZERO:
+ return ex_handler_fixup_err_zero(ex, regs);
}
return false;
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index c29f51ea8517..b36ac0d99176 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -371,19 +371,23 @@ static inline int copy_mc_highpage(struct page *to, struct page *from)
return ret ? -EFAULT : 0;
}
#else
+#ifndef __HAVE_ARCH_COPY_MC_USER_HIGHPAGE
static inline int copy_mc_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
copy_user_highpage(to, from, vaddr, vma);
return 0;
}
+#endif
+#ifndef __HAVE_ARCH_COPY_MC_HIGHPAGE
static inline int copy_mc_highpage(struct page *to, struct page *from)
{
copy_highpage(to, from);
return 0;
}
#endif
+#endif
static inline void memcpy_page(struct page *dst_page, size_t dst_off,
struct page *src_page, size_t src_off,
--
2.25.1