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x86, setup: mark %esi as clobbered in E820 BIOS call
Jordan Hargrave diagnosed a BIOS clobbering %esi in the E820 call. That particular BIOS has been fixed, but there is a possibility that this is responsible for other occasional reports of early boot failure, and it does not hurt to add %esi to the clobbers. -stable candidate patch. Cc: Justin Forbes <jmforbes@linuxtx.org> Signed-off-by: Michael K Johnson <johnsonm@rpath.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: stable@kernel.org
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@ -27,13 +27,14 @@ static int detect_memory_e820(void)
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do {
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do {
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size = sizeof(struct e820entry);
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size = sizeof(struct e820entry);
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/* Important: %edx is clobbered by some BIOSes,
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/* Important: %edx and %esi are clobbered by some BIOSes,
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so it must be either used for the error output
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so they must be either used for the error output
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or explicitly marked clobbered. */
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or explicitly marked clobbered. */
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asm("int $0x15; setc %0"
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asm("int $0x15; setc %0"
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: "=d" (err), "+b" (next), "=a" (id), "+c" (size),
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: "=d" (err), "+b" (next), "=a" (id), "+c" (size),
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"=m" (*desc)
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"=m" (*desc)
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: "D" (desc), "d" (SMAP), "a" (0xe820));
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: "D" (desc), "d" (SMAP), "a" (0xe820)
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: "esi");
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/* BIOSes which terminate the chain with CF = 1 as opposed
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/* BIOSes which terminate the chain with CF = 1 as opposed
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to %ebx = 0 don't always report the SMAP signature on
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to %ebx = 0 don't always report the SMAP signature on
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