From: Andrew Cooper Date: Thu, 23 Oct 2014 08:18:29 +0000 (+0200) Subject: x86/setup: correct register clobbers for the asm statement when resyncing the stack X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~4158 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=0d3a7bcd0b1181c9dc0fb04ef3abdfcdb5f20441;p=xen.git x86/setup: correct register clobbers for the asm statement when resyncing the stack When resyncing the stack, the asm statement does not identify %rsi, %rdi and %rcx as clobbered by the 'rep movsq'. Luckily, there are no functional problems in the generated code. GCC decides not to save any of them before calling boostrap_map(), which clobbers them. Correct the clobbers, by listing them as earlyclobber discarded outputs. Reported-by: Daniel Kiper Signed-off-by: Andrew Cooper Reviewed-by: Daniel Kiper Tested-by: Daniel Kiper --- diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index bfbb310afb..73e95c69a7 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -902,11 +902,13 @@ void __init noreturn __start_xen(unsigned long mbi_p) "movq %%cr4,%%rsi ; " "andb $0x7f,%%sil ; " "movq %%rsi,%%cr4 ; " /* CR4.PGE == 0 */ - "movq %0,%%cr3 ; " /* CR3 == new pagetables */ + "movq %[pg],%%cr3 ; " /* CR3 == new pagetables */ "orb $0x80,%%sil ; " "movq %%rsi,%%cr4 " /* CR4.PGE == 1 */ - : : "r" (__pa(idle_pg_table)), "S" (cpu0_stack), - "D" (__va(__pa(cpu0_stack))), "c" (STACK_SIZE / 8) : "memory" ); + : "=&S" (i), "=&D" (i), "=&c" (i) /* All outputs discarded. */ + : [pg] "r" (__pa(idle_pg_table)), "0" (cpu0_stack), + "1" (__va(__pa(cpu0_stack))), "2" (STACK_SIZE / 8) + : "memory" ); bootstrap_map(NULL); }