From 8ab4b00442759ff9b61f5e813b73d29d91c4ae5f Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Mon, 2 Mar 2015 15:21:38 +0000 Subject: [PATCH] [libc] Rewrite setjmp() and longjmp() Signed-off-by: Michael Brown --- src/arch/i386/core/setjmp.S | 84 +++++++++++++++++++++------------- src/arch/i386/include/setjmp.h | 46 +++++++++++-------- 2 files changed, 81 insertions(+), 49 deletions(-) diff --git a/src/arch/i386/core/setjmp.S b/src/arch/i386/core/setjmp.S index 03727148c..68277b990 100644 --- a/src/arch/i386/core/setjmp.S +++ b/src/arch/i386/core/setjmp.S @@ -1,42 +1,64 @@ -/* setjmp and longjmp. Use of these functions is deprecated. */ - -FILE_LICENCE ( GPL2_OR_LATER ) +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ) .text .arch i386 .code32 - -/************************************************************************** -SETJMP - Save stack context for non-local goto -**************************************************************************/ + + /* Must match jmp_buf structure layout */ + .struct 0 +env_retaddr: .long 0 +env_stack: .long 0 +env_ebx: .long 0 +env_esi: .long 0 +env_edi: .long 0 +env_ebp: .long 0 + .previous + +/* + * Save stack context for non-local goto + */ .globl setjmp setjmp: - movl 4(%esp),%ecx /* jmpbuf */ - movl 0(%esp),%edx /* return address */ - movl %edx,0(%ecx) - movl %ebx,4(%ecx) - movl %esp,8(%ecx) - movl %ebp,12(%ecx) - movl %esi,16(%ecx) - movl %edi,20(%ecx) - movl $0,%eax + /* Get jmp_buf pointer in %edx */ + movl 4(%esp),%edx + /* Save return address */ + movl 0(%esp),%eax + movl %eax, env_retaddr(%edx) + /* Save stack pointer */ + movl %esp, env_stack(%edx) + /* Save other registers */ + movl %ebx, env_ebx(%edx) + movl %esi, env_esi(%edx) + movl %edi, env_edi(%edx) + movl %ebp, env_ebp(%edx) + /* Return 0 when returning as setjmp() */ + xorl %eax, %eax ret + .size setjmp, . - setjmp -/************************************************************************** -LONGJMP - Non-local jump to a saved stack context -**************************************************************************/ +/* + * Non-local jump to a saved stack context + */ .globl longjmp longjmp: - movl 4(%esp),%edx /* jumpbuf */ - movl 8(%esp),%eax /* result */ - movl 0(%edx),%ecx - movl 4(%edx),%ebx - movl 8(%edx),%esp - movl 12(%edx),%ebp - movl 16(%edx),%esi - movl 20(%edx),%edi - cmpl $0,%eax - jne 1f - movl $1,%eax -1: movl %ecx,0(%esp) + /* Get jmp_buf pointer in %edx */ + movl 4(%esp),%edx + /* Get result in %eax */ + movl 8(%esp),%eax + /* Force result to non-zero */ + testl %eax, %eax + jnz 1f + incl %eax +1: /* Restore stack pointer */ + movl env_stack(%edx), %esp + /* Restore other registers */ + movl env_ebx(%edx), %esp + movl env_esi(%edx), %esp + movl env_edi(%edx), %esp + movl env_ebp(%edx), %ebp + /* Replace return address on the new stack */ + popl %ecx /* discard */ + pushl env_retaddr(%edx) + /* Return to setjmp() caller */ ret + .size longjmp, . - longjmp diff --git a/src/arch/i386/include/setjmp.h b/src/arch/i386/include/setjmp.h index 5d3c11b69..fe1a9ef4d 100644 --- a/src/arch/i386/include/setjmp.h +++ b/src/arch/i386/include/setjmp.h @@ -1,40 +1,50 @@ -#ifndef ETHERBOOT_SETJMP_H -#define ETHERBOOT_SETJMP_H +#ifndef _SETJMP_H +#define _SETJMP_H -FILE_LICENCE ( GPL2_OR_LATER ); +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include #include /** A jump buffer */ typedef struct { + /** Saved return address */ uint32_t retaddr; + /** Saved stack pointer */ + uint32_t stack; + /** Saved %ebx */ uint32_t ebx; - uint32_t esp; - uint32_t ebp; + /** Saved %esi */ uint32_t esi; + /** Saved %edi */ uint32_t edi; + /** Saved %ebp */ + uint32_t ebp; } jmp_buf[1]; /** A real-mode-extended jump buffer */ typedef struct { + /** Jump buffer */ jmp_buf env; - uint16_t rm_ss; - uint16_t rm_sp; + /** Real-mode stack pointer */ + segoff_t rm_stack; } rmjmp_buf[1]; -extern int __asmcall setjmp ( jmp_buf env ); -extern void __asmcall longjmp ( jmp_buf env, int val ); +extern int __asmcall __attribute__ (( returns_twice )) +setjmp ( jmp_buf env ); -#define rmsetjmp( _env ) ( { \ - (_env)->rm_ss = rm_ss; \ - (_env)->rm_sp = rm_sp; \ - setjmp ( (_env)->env ); } ) \ +extern void __asmcall __attribute__ (( noreturn )) +longjmp ( jmp_buf env, int val ); -#define rmlongjmp( _env, _val ) do { \ - rm_ss = (_env)->rm_ss; \ - rm_sp = (_env)->rm_sp; \ - longjmp ( (_env)->env, (_val) ); \ +#define rmsetjmp( _env ) ( { \ + (_env)->rm_stack.segment = rm_ss; \ + (_env)->rm_stack.offset = rm_sp; \ + setjmp ( (_env)->env ); } ) \ + +#define rmlongjmp( _env, _val ) do { \ + rm_ss = (_env)->rm_stack.segment; \ + rm_sp = (_env)->rm_stack.offset; \ + longjmp ( (_env)->env, (_val) ); \ } while ( 0 ) -#endif /* ETHERBOOT_SETJMP_H */ +#endif /* _SETJMP_H */