From f7ff53e4702be9ac49deacd518dd243de45c9980 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Mon, 12 Mar 2018 13:02:44 +0300 Subject: [PATCH] x86/boot/compressed/64: Use stack from trampoline memory 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 Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Cyrill Gorcunov Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180312100246.89175-3-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar --- 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..12915511be61 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -33,6 +33,7 @@ #include #include #include +#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 + /* Set up new stack */ + leal TRAMPOLINE_32BIT_STACK_END(%ecx), %esp + /* Disable paging */ movl %cr0, %eax btrl $X86_CR0_PG_BIT, %eax -- GitLab