6.1-stable review patch. If anyone has any objections, please let me know.
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From: Ard Biesheuvel ardb@kernel.org
commit c6355995ba471d7ad574174e593192ce805c7e1a upstream.
Convert startup32_load_idt() into an ordinary function and move it into the .text section. This involves turning the rva() immediates into ones derived from a local label, and preserving/restoring the %ebp and %ebx as per the calling convention.
Also move the #ifdef to the only existing call site. This makes it clear that the function call does nothing if support for memory encryption is not compiled in.
Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Borislav Petkov bp@suse.de Link: https://lore.kernel.org/r/20221122161017.2426828-12-ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/boot/compressed/head_64.S | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-)
--- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -118,7 +118,9 @@ SYM_FUNC_START(startup_32) 1:
/* Setup Exception handling for SEV-ES */ +#ifdef CONFIG_AMD_MEM_ENCRYPT call startup32_load_idt +#endif
/* Make sure cpu supports long mode. */ call verify_cpu @@ -732,10 +734,8 @@ SYM_DATA_START(boot32_idt) .quad 0 .endr SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLOBAL, boot32_idt_end) -#endif
-#ifdef CONFIG_AMD_MEM_ENCRYPT - __HEAD + .text .code32 /* * Write an IDT entry into boot32_idt @@ -768,24 +768,32 @@ SYM_FUNC_START_LOCAL(startup32_set_idt_e
RET SYM_FUNC_END(startup32_set_idt_entry) -#endif
SYM_FUNC_START(startup32_load_idt) -#ifdef CONFIG_AMD_MEM_ENCRYPT - leal rva(boot32_idt)(%ebp), %ecx + push %ebp + push %ebx + + call 1f +1: pop %ebp + + leal (boot32_idt - 1b)(%ebp), %ebx
/* #VC handler */ - leal rva(startup32_vc_handler)(%ebp), %eax + leal (startup32_vc_handler - 1b)(%ebp), %eax movl $X86_TRAP_VC, %edx + movl %ebx, %ecx call startup32_set_idt_entry
/* Load IDT */ - leal rva(boot32_idt)(%ebp), %eax - movl %eax, rva(boot32_idt_desc+2)(%ebp) - lidt rva(boot32_idt_desc)(%ebp) -#endif + leal (boot32_idt_desc - 1b)(%ebp), %ecx + movl %ebx, 2(%ecx) + lidt (%ecx) + + pop %ebx + pop %ebp RET SYM_FUNC_END(startup32_load_idt) +#endif
/* * Check for the correct C-bit position when the startup_32 boot-path is used. @@ -804,6 +812,7 @@ SYM_FUNC_END(startup32_load_idt) * succeed. An incorrect C-bit position will map all memory unencrypted, so that * the compare will use the encrypted random data and fail. */ + __HEAD SYM_FUNC_START(startup32_check_sev_cbit) #ifdef CONFIG_AMD_MEM_ENCRYPT pushl %eax