[libc] Rewrite setjmp() and longjmp()
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
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d1f0e89e4e
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8ab4b00442
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/* setjmp and longjmp. Use of these functions is deprecated. */
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FILE_LICENCE ( GPL2_OR_LATER )
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL )
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.text
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.arch i386
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.code32
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/**************************************************************************
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SETJMP - Save stack context for non-local goto
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**************************************************************************/
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/* Must match jmp_buf structure layout */
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.struct 0
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env_retaddr: .long 0
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env_stack: .long 0
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env_ebx: .long 0
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env_esi: .long 0
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env_edi: .long 0
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env_ebp: .long 0
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.previous
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/*
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* Save stack context for non-local goto
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*/
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.globl setjmp
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setjmp:
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movl 4(%esp),%ecx /* jmpbuf */
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movl 0(%esp),%edx /* return address */
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movl %edx,0(%ecx)
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movl %ebx,4(%ecx)
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movl %esp,8(%ecx)
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movl %ebp,12(%ecx)
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movl %esi,16(%ecx)
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movl %edi,20(%ecx)
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movl $0,%eax
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/* Get jmp_buf pointer in %edx */
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movl 4(%esp),%edx
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/* Save return address */
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movl 0(%esp),%eax
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movl %eax, env_retaddr(%edx)
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/* Save stack pointer */
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movl %esp, env_stack(%edx)
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/* Save other registers */
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movl %ebx, env_ebx(%edx)
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movl %esi, env_esi(%edx)
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movl %edi, env_edi(%edx)
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movl %ebp, env_ebp(%edx)
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/* Return 0 when returning as setjmp() */
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xorl %eax, %eax
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ret
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.size setjmp, . - setjmp
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/**************************************************************************
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LONGJMP - Non-local jump to a saved stack context
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**************************************************************************/
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/*
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* Non-local jump to a saved stack context
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*/
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.globl longjmp
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longjmp:
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movl 4(%esp),%edx /* jumpbuf */
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movl 8(%esp),%eax /* result */
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movl 0(%edx),%ecx
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movl 4(%edx),%ebx
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movl 8(%edx),%esp
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movl 12(%edx),%ebp
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movl 16(%edx),%esi
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movl 20(%edx),%edi
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cmpl $0,%eax
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jne 1f
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movl $1,%eax
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1: movl %ecx,0(%esp)
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/* Get jmp_buf pointer in %edx */
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movl 4(%esp),%edx
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/* Get result in %eax */
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movl 8(%esp),%eax
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/* Force result to non-zero */
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testl %eax, %eax
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jnz 1f
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incl %eax
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1: /* Restore stack pointer */
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movl env_stack(%edx), %esp
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/* Restore other registers */
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movl env_ebx(%edx), %esp
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movl env_esi(%edx), %esp
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movl env_edi(%edx), %esp
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movl env_ebp(%edx), %ebp
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/* Replace return address on the new stack */
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popl %ecx /* discard */
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pushl env_retaddr(%edx)
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/* Return to setjmp() caller */
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ret
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.size longjmp, . - longjmp
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@ -1,40 +1,50 @@
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#ifndef ETHERBOOT_SETJMP_H
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#define ETHERBOOT_SETJMP_H
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#ifndef _SETJMP_H
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#define _SETJMP_H
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FILE_LICENCE ( GPL2_OR_LATER );
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <realmode.h>
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/** A jump buffer */
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typedef struct {
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/** Saved return address */
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uint32_t retaddr;
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/** Saved stack pointer */
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uint32_t stack;
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/** Saved %ebx */
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uint32_t ebx;
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uint32_t esp;
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uint32_t ebp;
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/** Saved %esi */
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uint32_t esi;
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/** Saved %edi */
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uint32_t edi;
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/** Saved %ebp */
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uint32_t ebp;
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} jmp_buf[1];
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/** A real-mode-extended jump buffer */
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typedef struct {
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/** Jump buffer */
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jmp_buf env;
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uint16_t rm_ss;
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uint16_t rm_sp;
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/** Real-mode stack pointer */
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segoff_t rm_stack;
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} rmjmp_buf[1];
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extern int __asmcall setjmp ( jmp_buf env );
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extern void __asmcall longjmp ( jmp_buf env, int val );
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extern int __asmcall __attribute__ (( returns_twice ))
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setjmp ( jmp_buf env );
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#define rmsetjmp( _env ) ( { \
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(_env)->rm_ss = rm_ss; \
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(_env)->rm_sp = rm_sp; \
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setjmp ( (_env)->env ); } ) \
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extern void __asmcall __attribute__ (( noreturn ))
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longjmp ( jmp_buf env, int val );
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#define rmlongjmp( _env, _val ) do { \
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rm_ss = (_env)->rm_ss; \
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rm_sp = (_env)->rm_sp; \
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longjmp ( (_env)->env, (_val) ); \
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#define rmsetjmp( _env ) ( { \
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(_env)->rm_stack.segment = rm_ss; \
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(_env)->rm_stack.offset = rm_sp; \
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setjmp ( (_env)->env ); } ) \
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#define rmlongjmp( _env, _val ) do { \
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rm_ss = (_env)->rm_stack.segment; \
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rm_sp = (_env)->rm_stack.offset; \
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longjmp ( (_env)->env, (_val) ); \
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} while ( 0 )
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#endif /* ETHERBOOT_SETJMP_H */
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#endif /* _SETJMP_H */
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