Messages in this thread Patch in this message | | | From | Joerg Roedel <> | Subject | [PATCH 3/7] x86/boot/compressed/64: Setup IDT in startup_32 boot path | Date | Wed, 10 Feb 2021 11:21:31 +0100 |
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From: Joerg Roedel <jroedel@suse.de>
This boot path needs exception handling when it is used with SEV-ES. Setup an IDT and provide a helper function to write IDT entries for use in 32-bit protected mode.
Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/boot/compressed/head_64.S | 73 +++++++++++++++++++++++++++++- 1 file changed, 72 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index c59c80ca546d..8deeec78cdb4 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -116,6 +116,11 @@ SYM_FUNC_START(startup_32) lretl 1: +#ifdef CONFIG_AMD_MEM_ENCRYPT + /* Setup Exception handling for SEV-ES */ + call startup32_load_idt +#endif + /* Make sure cpu supports long mode. */ call verify_cpu testl %eax, %eax @@ -528,7 +533,6 @@ SYM_FUNC_END_ALIAS(efi_stub_entry) .text SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) - /* * Clear BSS (stack is currently empty) */ @@ -701,6 +705,19 @@ SYM_DATA_START(boot_idt) .endr SYM_DATA_END_LABEL(boot_idt, SYM_L_GLOBAL, boot_idt_end) +#ifdef CONFIG_AMD_MEM_ENCRYPT +SYM_DATA_START(boot32_idt_desc) + .word boot32_idt_end - boot32_idt - 1 + .long 0 +SYM_DATA_END(boot32_idt_desc) + .balign 8 +SYM_DATA_START(boot32_idt) + .rept 32 + .quad 0 + .endr +SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLOBAL, boot32_idt_end) +#endif + #ifdef CONFIG_EFI_STUB SYM_DATA(image_offset, .long 0) #endif @@ -793,6 +810,60 @@ SYM_DATA_START_LOCAL(loaded_image_proto) SYM_DATA_END(loaded_image_proto) #endif +#ifdef CONFIG_AMD_MEM_ENCRYPT + __HEAD + .code32 +/* + * Write an IDT entry into boot32_idt + * + * Parameters: + * + * %eax: Handler address + * %edx: Vector number + * + * Physical offset is expected in %ebp + */ +SYM_FUNC_START(startup32_set_idt_entry) + push %ebx + push %ecx + + /* IDT entry address to %ebx */ + leal rva(boot32_idt)(%ebp), %ebx + shl $3, %edx + addl %edx, %ebx + + /* Build IDT entry, lower 4 bytes */ + movl %eax, %edx + andl $0x0000ffff, %edx + movl $__KERNEL32_CS, %ecx + shl $16, %ecx + orl %ecx, %edx + + /* Store lower 4 bytes to IDT */ + movl %edx, (%ebx) + + /* Build IDT entry, upper 4 bytes */ + movl %eax, %edx + andl $0xffff0000, %edx + orl $0x00008e00, %edx + + /* Store upper 4 bytes to IDT */ + movl %edx, 4(%ebx) + + pop %ecx + pop %ebx + ret +SYM_FUNC_END(startup32_set_idt_entry) + +SYM_FUNC_START(startup32_load_idt) + /* Load IDT */ + leal rva(boot32_idt)(%ebp), %eax + movl %eax, rva(boot32_idt_desc+2)(%ebp) + lidt rva(boot32_idt_desc)(%ebp) + + ret +SYM_FUNC_END(startup32_load_idt) +#endif /* * Stack and heap for uncompression */ -- 2.30.0
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