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

Tong Tiangen <tongtiangen@xxxxxxxxxx> · Sat, 18 Jun 2022 10:44:50 +0800

在 2022/6/17 16:23, Mark Rutland 写道:
On Sat, May 28, 2022 at 06:50:49AM +0000, Tong Tiangen wrote:
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@xxxxxxx>
Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>

This looks good to me, so modulo one nit below:

Acked-by: Mark Rutland <mark.rutland@xxxxxxx>

---
  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

Could we please renumber this so the UACCESS and KACCESS definitions are next
to one another, i.e.

#define EX_TYPE_BPF			2
#define EX_TYPE_UACCESS_ERR_ZERO	3
#define EX_TYPE_KACCESS_ERR_ZERO	4
#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD	5

Thanks,
Mark.

ok, It's cleaner.

Thanks,
Tong.


  
  #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


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