Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCH 2/4] x86/boot/compressed/64: Use stack from trampoline memory | Date | Mon, 12 Mar 2018 13:02:44 +0300 |
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As the first step on using trampoline memory, let's make 32-bit code use stack there.
Separate stack is required to return back from trampoline and we cannot user stack from 64-bit mode as it may be above 4G.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> --- arch/x86/boot/compressed/head_64.S | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index f0c3a2f7e528..0014459d9bcb 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -33,6 +33,7 @@ #include <asm/processor-flags.h> #include <asm/asm-offsets.h> #include <asm/bootparam.h> +#include "pgtable.h" /* * Locally defined symbols should be marked hidden: @@ -359,6 +360,8 @@ ENTRY(startup_64) pushq %rax lretq lvl5: + /* Restore the stack, the 32-bit trampoline uses its own stack */ + leaq boot_stack_end(%rbx), %rsp /* * cleanup_trampoline() would restore trampoline memory. @@ -513,6 +516,9 @@ compatible_mode: movl %eax, %ds movl %eax, %ss + /* Setup new stack */ + leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp + /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax -- 2.16.1
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