2004-11-11 16:18:58

by Kirill Korotaev

[permalink] [raw]
Subject: [PATCH]: 4/4GB:

--- ./arch/i386/kernel/entry.S.4gbrest 2004-11-10 11:21:32.000000000 +0300
+++ ./arch/i386/kernel/entry.S 2004-11-10 12:35:24.239613040 +0300
@@ -167,7 +167,7 @@ int80_ret_start_marker: \
movl %edx, %esp; \
movl %ecx, %cr3; \
\
- __RESTORE_ALL; \
+ __RESTORE_ALL_USER; \
int80_ret_end_marker: \
2:

@@ -204,14 +204,19 @@ int80_ret_end_marker: \

#define __RESTORE_REGS \
__RESTORE_INT_REGS; \
+ popl %ds; \
+ popl %es;
+
+#define __RESTORE_REGS_USER \
+ __RESTORE_INT_REGS; \
111: popl %ds; \
222: popl %es; \
-.section .fixup,"ax"; \
+ jmp 666f; \
444: movl $0,(%esp); \
jmp 111b; \
555: movl $0,(%esp); \
jmp 222b; \
-.previous; \
+666: \
.section __ex_table,"a";\
.align 4; \
.long 111b,444b;\
@@ -220,6 +225,13 @@ int80_ret_end_marker: \

#define __RESTORE_ALL \
__RESTORE_REGS \
+ __RESTORE_IRET
+
+#define __RESTORE_ALL_USER \
+ __RESTORE_REGS_USER \
+ __RESTORE_IRET
+
+#define __RESTORE_IRET \
addl $4, %esp; \
333: iret; \
.section .fixup,"ax"; \


Attachments:
diff-arch-4gb-restore (1.01 kB)

2004-11-12 19:23:40

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH]: 4/4GB:


* Kirill Korotaev <[email protected]> wrote:

> #define __RESTORE_REGS \
> __RESTORE_INT_REGS; \
> + popl %ds; \
> + popl %es;
> +
> +#define __RESTORE_REGS_USER \
> + __RESTORE_INT_REGS; \
> 111: popl %ds; \
> 222: popl %es; \
> -.section .fixup,"ax"; \
> + jmp 666f; \
> 444: movl $0,(%esp); \
> jmp 111b; \
> 555: movl $0,(%esp); \
> jmp 222b; \
> -.previous; \
> +666: \
> .section __ex_table,"a";\
> .align 4; \
> .long 111b,444b;\
> @@ -220,6 +225,13 @@ int80_ret_end_marker: \
>
> #define __RESTORE_ALL \
> __RESTORE_REGS \
> + __RESTORE_IRET
> +
> +#define __RESTORE_ALL_USER \
> + __RESTORE_REGS_USER \
> + __RESTORE_IRET
> +
> +#define __RESTORE_IRET \
> addl $4, %esp; \
> 333: iret; \
> .section .fixup,"ax"; \

looks fine and necessary. Fundamental bugs in this area tend to show up
as instant reboots, so i'm sure if you broke this code you'll quickly
notice it ...

Ingo