Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] x86/boot/compressed/64: fix warning for 32-bit trampoline copy | Date | Thu, 22 Feb 2018 11:40:41 +0100 |
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gcc-8 warns that we copy TRAMPOLINE_32BIT_CODE_SIZE bytes from the pointer to the function into actual trampoline, when that pointer is only 8 bytes:
In file included from arch/x86/boot/compressed/pgtable_64.c:3: arch/x86/boot/compressed/pgtable_64.c: In function 'paging_prepare': arch/x86/boot/compressed/../string.h:18:23: error: '__builtin_memcpy' reading 96 bytes from a region of size 8 [-Werror=stringop-overflow=] #define memcpy(d,s,l) __builtin_memcpy(d,s,l) ^~~~~~~~~~~~~~~~~~~~~~~ arch/x86/boot/compressed/pgtable_64.c:62:2: note: in expansion of macro 'memcpy' memcpy(trampoline + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned long), ^~~~~~
I assume what was intended here is to copy the trampoline itself rather than the pointer to the trampoline.
Cc: Martin Sebor <msebor@gmail.com> Fixes: b91993a87aff ("x86/boot/compressed/64: Prepare trampoline memory") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- This is a fairly new warning in gcc, it's possible that the code is correct and the warning message got it wrong, please double-check this.
Was the 32-bit trampoline code in the 64-bit decompressor tested successfully? --- arch/x86/boot/compressed/pgtable_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/pgtable_64.c b/arch/x86/boot/compressed/pgtable_64.c index dad5da7b4c1a..35a0542fe397 100644 --- a/arch/x86/boot/compressed/pgtable_64.c +++ b/arch/x86/boot/compressed/pgtable_64.c @@ -60,7 +60,7 @@ struct paging_config paging_prepare(void) /* Copy trampoline code in place */ memcpy(trampoline + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned long), - &trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); + trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); /* * Set up a new page table that will be used for switching from 4- -- 2.9.0
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