Skip to content

Commit

Permalink
x86/boot/compressed: Move startup32_load_idt() out of head_64.S
Browse files Browse the repository at this point in the history
Now that startup32_load_idt() has been refactored into an ordinary
callable function, move it into mem-encrypt.S where it belongs.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-13-ardb@kernel.org
  • Loading branch information
ardbiesheuvel authored and suryasaimadhu committed Nov 24, 2022
1 parent c635599 commit 9ea813b
Show file tree
Hide file tree
Showing 2 changed files with 71 additions and 73 deletions.
72 changes: 0 additions & 72 deletions arch/x86/boot/compressed/head_64.S
Original file line number Diff line number Diff line change
Expand Up @@ -707,78 +707,6 @@ 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)

.text
.code32
/*
* Write an IDT entry into boot32_idt
*
* Parameters:
*
* %eax: Handler address
* %edx: Vector number
* %ecx: IDT address
*/
SYM_FUNC_START_LOCAL(startup32_set_idt_entry)
/* IDT entry address to %ecx */
leal (%ecx, %edx, 8), %ecx

/* Build IDT entry, lower 4 bytes */
movl %eax, %edx
andl $0x0000ffff, %edx # Target code segment offset [15:0]
orl $(__KERNEL32_CS << 16), %edx # Target code segment selector

/* Store lower 4 bytes to IDT */
movl %edx, (%ecx)

/* Build IDT entry, upper 4 bytes */
movl %eax, %edx
andl $0xffff0000, %edx # Target code segment offset [31:16]
orl $0x00008e00, %edx # Present, Type 32-bit Interrupt Gate

/* Store upper 4 bytes to IDT */
movl %edx, 4(%ecx)

RET
SYM_FUNC_END(startup32_set_idt_entry)

SYM_FUNC_START(startup32_load_idt)
push %ebp
push %ebx

call 1f
1: pop %ebp

leal (boot32_idt - 1b)(%ebp), %ebx

/* #VC handler */
leal (startup32_vc_handler - 1b)(%ebp), %eax
movl $X86_TRAP_VC, %edx
movl %ebx, %ecx
call startup32_set_idt_entry

/* Load IDT */
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.
*
Expand Down
72 changes: 71 additions & 1 deletion arch/x86/boot/compressed/mem_encrypt.S
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@
#include <asm/processor-flags.h>
#include <asm/msr.h>
#include <asm/asm-offsets.h>
#include <asm/segment.h>
#include <asm/trapnr.h>

.text
.code32
Expand Down Expand Up @@ -98,7 +100,7 @@ SYM_CODE_START_LOCAL(sev_es_req_cpuid)
jmp 1b
SYM_CODE_END(sev_es_req_cpuid)

SYM_CODE_START(startup32_vc_handler)
SYM_CODE_START_LOCAL(startup32_vc_handler)
pushl %eax
pushl %ebx
pushl %ecx
Expand Down Expand Up @@ -184,6 +186,63 @@ SYM_CODE_START(startup32_vc_handler)
jmp .Lfail
SYM_CODE_END(startup32_vc_handler)

/*
* Write an IDT entry into boot32_idt
*
* Parameters:
*
* %eax: Handler address
* %edx: Vector number
* %ecx: IDT address
*/
SYM_FUNC_START_LOCAL(startup32_set_idt_entry)
/* IDT entry address to %ecx */
leal (%ecx, %edx, 8), %ecx

/* Build IDT entry, lower 4 bytes */
movl %eax, %edx
andl $0x0000ffff, %edx # Target code segment offset [15:0]
orl $(__KERNEL32_CS << 16), %edx # Target code segment selector

/* Store lower 4 bytes to IDT */
movl %edx, (%ecx)

/* Build IDT entry, upper 4 bytes */
movl %eax, %edx
andl $0xffff0000, %edx # Target code segment offset [31:16]
orl $0x00008e00, %edx # Present, Type 32-bit Interrupt Gate

/* Store upper 4 bytes to IDT */
movl %edx, 4(%ecx)

RET
SYM_FUNC_END(startup32_set_idt_entry)

SYM_FUNC_START(startup32_load_idt)
push %ebp
push %ebx

call 1f
1: pop %ebp

leal (boot32_idt - 1b)(%ebp), %ebx

/* #VC handler */
leal (startup32_vc_handler - 1b)(%ebp), %eax
movl $X86_TRAP_VC, %edx
movl %ebx, %ecx
call startup32_set_idt_entry

/* Load IDT */
leal (boot32_idt_desc - 1b)(%ebp), %ecx
movl %ebx, 2(%ecx)
lidt (%ecx)

pop %ebx
pop %ebp
RET
SYM_FUNC_END(startup32_load_idt)

.code64

#include "../../kernel/sev_verify_cbit.S"
Expand All @@ -195,4 +254,15 @@ SYM_CODE_END(startup32_vc_handler)
SYM_DATA(sme_me_mask, .quad 0)
SYM_DATA(sev_status, .quad 0)
SYM_DATA(sev_check_data, .quad 0)

SYM_DATA_START_LOCAL(boot32_idt)
.rept 32
.quad 0
.endr
SYM_DATA_END(boot32_idt)

SYM_DATA_START_LOCAL(boot32_idt_desc)
.word . - boot32_idt - 1
.long 0
SYM_DATA_END(boot32_idt_desc)
#endif

0 comments on commit 9ea813b

Please sign in to comment.