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powerpc/uaccess: Use unsafe wrappers for ASM GOTO

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ASM GOTO is miscompiled by GCC when it is used inside a auto cleanup scope:

bool foo(u32 __user *p, u32 val)
{
	scoped_guard(pagefault)
		unsafe_put_user(val, p, efault);
	return true;
efault:
	return false;
}

It ends up leaking the pagefault disable counter in the fault path. clang
at least fails the build.

Rename unsafe_*_user() to arch_unsafe_*_user() which makes the generic
uaccess header wrap it with a local label that makes both compilers emit
correct code. Same for the kernel_nofault() variants.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027083745.356628509@linutronix.de
This commit is contained in:
Thomas Gleixner
2025-10-27 09:43:48 +01:00
committed by Peter Zijlstra
parent 14219398e3
commit 5002dd5314
1 changed files with 4 additions and 4 deletions
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8
arch/powerpc/include/asm/uaccess.h
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@@ -451,7 +451,7 @@ user_write_access_begin(const void __user *ptr, size_t len)
#define user_write_access_begin user_write_access_begin
#define user_write_access_end prevent_current_write_to_user
#define unsafe_get_user(x, p, e) do { \
#define arch_unsafe_get_user(x, p, e) do { \
__long_type(*(p)) __gu_val; \
__typeof__(*(p)) __user *__gu_addr = (p); \
\
@@ -459,7 +459,7 @@ user_write_access_begin(const void __user *ptr, size_t len)
(x) = (__typeof__(*(p)))__gu_val; \
} while (0)
#define unsafe_put_user(x, p, e) \
#define arch_unsafe_put_user(x, p, e) \
__put_user_size_goto((__typeof__(*(p)))(x), (p), sizeof(*(p)), e)
#define unsafe_copy_from_user(d, s, l, e) \
@@ -504,11 +504,11 @@ do { \
unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
} while (0)
#define __get_kernel_nofault(dst, src, type, err_label) \
#define arch_get_kernel_nofault(dst, src, type, err_label) \
__get_user_size_goto(*((type *)(dst)), \
(__force type __user *)(src), sizeof(type), err_label)
#define __put_kernel_nofault(dst, src, type, err_label) \
#define arch_put_kernel_nofault(dst, src, type, err_label) \
__put_user_size_goto(*((type *)(src)), \
(__force type __user *)(dst), sizeof(type), err_label)