[PATCH v11 05/15] x86/uaccess: Add unsafe_copy_from_user() implementation
From: Jens Remus <hidden>
Date: 2025-10-22 14:44:44
Also in:
bpf, linux-mm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Josh Poimboeuf <jpoimboe@kernel.org> Add an x86 implementation of unsafe_copy_from_user() similar to the existing unsafe_copy_to_user(). Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <redacted> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Indu Bhagat <redacted> Cc: "Jose E. Marchesi" <redacted> Cc: Beau Belgrave <redacted> Cc: Jens Remus <redacted> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Florian Weimer <redacted> Cc: Sam James <redacted> Cc: Kees Cook <kees@kernel.org> Cc: "Carlos O'Donell" <redacted> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Jens Remus <redacted> --- arch/x86/include/asm/uaccess.h | 39 +++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 3a7755c1a441..3caf02d0503e 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h@@ -599,7 +599,7 @@ _label: \ * We want the unsafe accessors to always be inlined and use * the error labels - thus the macro games. */ -#define unsafe_copy_loop(dst, src, len, type, label) \ +#define unsafe_copy_to_user_loop(dst, src, len, type, label) \ while (len >= sizeof(type)) { \ unsafe_put_user(*(type *)(src),(type __user *)(dst),label); \ dst += sizeof(type); \
@@ -607,15 +607,34 @@ _label: \ len -= sizeof(type); \ } -#define unsafe_copy_to_user(_dst,_src,_len,label) \ -do { \ - char __user *__ucu_dst = (_dst); \ - const char *__ucu_src = (_src); \ - size_t __ucu_len = (_len); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u64, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u32, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u16, label); \ - unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \ +#define unsafe_copy_to_user(_dst, _src, _len, label) \ +do { \ + void __user *__dst = (_dst); \ + const void *__src = (_src); \ + size_t __len = (_len); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u64, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u32, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u16, label); \ + unsafe_copy_to_user_loop(__dst, __src, __len, u8, label); \ +} while (0) + +#define unsafe_copy_from_user_loop(dst, src, len, type, label) \ + while (len >= sizeof(type)) { \ + unsafe_get_user(*(type *)(dst), (type __user *)(src), label); \ + dst += sizeof(type); \ + src += sizeof(type); \ + len -= sizeof(type); \ + } + +#define unsafe_copy_from_user(_dst, _src, _len, label) \ +do { \ + void *__dst = (_dst); \ + void __user *__src = (_src); \ + size_t __len = (_len); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u64, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u32, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u16, label); \ + unsafe_copy_from_user_loop(__dst, __src, __len, u8, label); \ } while (0) #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
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2.48.1