[PATCH -next v5 1/8] arm64: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support

Tong Tiangen
2022-05-28T06:32:12Z

Currently, The extable type EX_TYPE_UACCESS_ERR_ZERO is used by
__get/put_kernel_nofault(), but those helpers are not uaccess type, so we
add a new extable type EX_TYPE_KACCESS_ERR_ZERO which can be used by
__get/put_kernel_no_fault().

This is also to prepare for distinguishing the two types in machine check
safe process.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
---
arch/arm64/include/asm/asm-extable.h | 13 ++++
arch/arm64/include/asm/uaccess.h | 94 ++++++++++++++--------------
arch/arm64/mm/extable.c | 1 +
3 files changed, 61 insertions(+), 47 deletions(-)

diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h
index c39f2437e08e..56ebe183e78b 100644
--- a/arch/arm64/include/asm/asm-extable.h
+++ b/arch/arm64/include/asm/asm-extable.h
@@ -7,6 +7,7 @@
#define EX_TYPE_BPF 2
#define EX_TYPE_UACCESS_ERR_ZERO 3
#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
+#define EX_TYPE_KACCESS_ERR_ZERO 5

#ifdef __ASSEMBLY__

@@ -73,9 +74,21 @@
EX_DATA_REG(ZERO, zero) \
")")

+#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero) \
+ __DEFINE_ASM_GPR_NUMS \
+ __ASM_EXTABLE_RAW(#insn, #fixup, \
+ __stringify(EX_TYPE_KACCESS_ERR_ZERO), \
+ "(" \
+ EX_DATA_REG(ERR, err) " | " \
+ EX_DATA_REG(ZERO, zero) \
+ ")")
+
#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)

+#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err) \
+ _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
+
#define EX_DATA_REG_DATA_SHIFT 0
#define EX_DATA_REG_DATA GENMASK(4, 0)
#define EX_DATA_REG_ADDR_SHIFT 5
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 63f9c828f1a7..2fc9f0861769 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -232,34 +232,34 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
* The "__xxx_error" versions set the third argument to -EFAULT if an error
* occurs, and leave it unchanged on success.
*/
-#define __get_mem_asm(load, reg, x, addr, err) \
+#define __get_mem_asm(load, reg, x, addr, err, type) \
asm volatile( \
"1: " load " " reg "1, [%2]\n" \
"2:\n" \
- _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
+ _ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
: "+r" (err), "=&r" (x) \
: "r" (addr))

-#define __raw_get_mem(ldr, x, ptr, err) \
-do { \
- unsigned long __gu_val; \
- switch (sizeof(*(ptr))) { \
- case 1: \
- __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err)); \
- break; \
- case 2: \
- __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err)); \
- break; \
- case 4: \
- __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err)); \
- break; \
- case 8: \
- __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err)); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
- (x) = (__force __typeof__(*(ptr)))__gu_val; \
+#define __raw_get_mem(ldr, x, ptr, err, type) \
+do { \
+ unsigned long __gu_val; \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err), type); \
+ break; \
+ case 2: \
+ __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err), type); \
+ break; \
+ case 4: \
+ __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err), type); \
+ break; \
+ case 8: \
+ __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err), type); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
+ (x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0)

/*
@@ -274,7 +274,7 @@ do { \
__chk_user_ptr(ptr); \
\
uaccess_ttbr0_enable(); \
- __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err); \
+ __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err, U); \
uaccess_ttbr0_disable(); \
\
(x) = __rgu_val; \
@@ -314,40 +314,40 @@ do { \
\
__uaccess_enable_tco_async(); \
__raw_get_mem("ldr", *((type *)(__gkn_dst)), \
- (__force type *)(__gkn_src), __gkn_err); \
+ (__force type *)(__gkn_src), __gkn_err, K); \
__uaccess_disable_tco_async(); \
\
if (unlikely(__gkn_err)) \
goto err_label; \
} while (0)

-#define __put_mem_asm(store, reg, x, addr, err) \
+#define __put_mem_asm(store, reg, x, addr, err, type) \
asm volatile( \
"1: " store " " reg "1, [%2]\n" \
"2:\n" \
- _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \
+ _ASM_EXTABLE_##type##ACCESS_ERR(1b, 2b, %w0) \
: "+r" (err) \
: "r" (x), "r" (addr))

-#define __raw_put_mem(str, x, ptr, err) \
-do { \
- __typeof__(*(ptr)) __pu_val = (x); \
- switch (sizeof(*(ptr))) { \
- case 1: \
- __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err)); \
- break; \
- case 2: \
- __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err)); \
- break; \
- case 4: \
- __put_mem_asm(str, "%w", __pu_val, (ptr), (err)); \
- break; \
- case 8: \
- __put_mem_asm(str, "%x", __pu_val, (ptr), (err)); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
+#define __raw_put_mem(str, x, ptr, err, type) \
+do { \
+ __typeof__(*(ptr)) __pu_val = (x); \
+ switch (sizeof(*(ptr))) { \
+ case 1: \
+ __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err), type); \
+ break; \
+ case 2: \
+ __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err), type); \
+ break; \
+ case 4: \
+ __put_mem_asm(str, "%w", __pu_val, (ptr), (err), type); \
+ break; \
+ case 8: \
+ __put_mem_asm(str, "%x", __pu_val, (ptr), (err), type); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
} while (0)

/*
@@ -362,7 +362,7 @@ do { \
__chk_user_ptr(__rpu_ptr); \
\
uaccess_ttbr0_enable(); \
- __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err); \
+ __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err, U); \
uaccess_ttbr0_disable(); \
} while (0)

@@ -400,7 +400,7 @@ do { \
\
__uaccess_enable_tco_async(); \
__raw_put_mem("str", *((type *)(__pkn_src)), \
- (__force type *)(__pkn_dst), __pkn_err); \
+ (__force type *)(__pkn_dst), __pkn_err, K); \
__uaccess_disable_tco_async(); \
\
if (unlikely(__pkn_err)) \
diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c
index 489455309695..056591e5ca80 100644
--- a/arch/arm64/mm/extable.c
+++ b/arch/arm64/mm/extable.c
@@ -77,6 +77,7 @@ bool fixup_exception(struct pt_regs *regs)
case EX_TYPE_BPF:
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);
case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
return ex_handler_load_unaligned_zeropad(ex, regs);
--
2.25.1