[PATCH] Cleanup vm86 fault handling

Brian Gerst (bgerst@didntduck.org)
Mon, 13 Jan 2003 01:33:09 -0500


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This patch makes handle_vm86_trap() accept or reject traps, instead of
handling it in do_trap(). This enables some extra cleanups with the
general protection fault and cache flush fault.

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				Brian Gerst

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diff -urN linux-a1/arch/i386/kernel/traps.c linux-b1/arch/i386/kernel/traps.c --- linux-a1/arch/i386/kernel/traps.c Sat Jan 11 03:29:47 2003 +++ linux-b1/arch/i386/kernel/traps.c Sat Jan 11 03:30:22 2003 @@ -258,12 +258,6 @@ do_exit(SIGSEGV); } -static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err) -{ - if (!(regs->eflags & VM_MASK) && !(3 & regs->xcs)) - die(str, regs, err); -} - static inline unsigned long get_cr2(void) { unsigned long address; @@ -273,14 +267,11 @@ return address; } -static inline void do_trap(int trapnr, int signr, char *str, int vm86, +static inline void do_trap(int trapnr, int signr, char *str, struct pt_regs * regs, long error_code, siginfo_t *info) { - if (regs->eflags & VM_MASK) { - if (vm86) - goto vm86_trap; - goto trap_signal; - } + if (regs->eflags & VM_MASK) + goto vm86_trap; if (!(regs->xcs & 3)) goto kernel_trap; @@ -303,8 +294,8 @@ } vm86_trap: { - int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr); - if (ret) goto trap_signal; + if (handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr)) + goto trap_signal; return; } } @@ -312,7 +303,7 @@ #define DO_ERROR(trapnr, signr, str, name) \ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ { \ - do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \ + do_trap(trapnr, signr, str, regs, error_code, NULL); \ } #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ @@ -323,61 +314,23 @@ info.si_errno = 0; \ info.si_code = sicode; \ info.si_addr = (void *)siaddr; \ - do_trap(trapnr, signr, str, 0, regs, error_code, &info); \ -} - -#define DO_VM86_ERROR(trapnr, signr, str, name) \ -asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ -{ \ - do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \ + do_trap(trapnr, signr, str, regs, error_code, &info); \ } -#define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ -asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ -{ \ - siginfo_t info; \ - info.si_signo = signr; \ - info.si_errno = 0; \ - info.si_code = sicode; \ - info.si_addr = (void *)siaddr; \ - do_trap(trapnr, signr, str, 1, regs, error_code, &info); \ -} - -DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip) -DO_VM86_ERROR( 3, SIGTRAP, "int3", int3) -DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow) -DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds) +DO_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip) +DO_ERROR( 3, SIGTRAP, "int3", int3) +DO_ERROR( 4, SIGSEGV, "overflow", overflow) +DO_ERROR( 5, SIGSEGV, "bounds", bounds) DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->eip) -DO_VM86_ERROR( 7, SIGSEGV, "device not available", device_not_available) +DO_ERROR( 7, SIGSEGV, "device not available", device_not_available) DO_ERROR( 8, SIGSEGV, "double fault", double_fault) DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun) DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS) DO_ERROR(11, SIGBUS, "segment not present", segment_not_present) DO_ERROR(12, SIGBUS, "stack segment", stack_segment) +DO_ERROR(13, SIGSEGV, "general protection fault", general_protection) DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, get_cr2()) -asmlinkage void do_general_protection(struct pt_regs * regs, long error_code) -{ - if (regs->eflags & VM_MASK) - goto gp_in_vm86; - - if (!(regs->xcs & 3)) - goto gp_in_kernel; - - current->thread.error_code = error_code; - current->thread.trap_no = 13; - force_sig(SIGSEGV, current); - return; - -gp_in_vm86: - handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code); - return; - -gp_in_kernel: - if (!fixup_exception(regs)) - die("general protection fault", regs, error_code); -} - static void mem_parity_error(unsigned char reason, struct pt_regs * regs) { printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n"); @@ -703,15 +656,7 @@ * Handle strange cache flush from user space exception * in all other cases. This is undocumented behaviour. */ - if (regs->eflags & VM_MASK) { - handle_vm86_fault((struct kernel_vm86_regs *)regs, - error_code); - return; - } - die_if_kernel("cache flush denied", regs, error_code); - current->thread.trap_no = 19; - current->thread.error_code = error_code; - force_sig(SIGSEGV, current); + do_trap(19, SIGSEGV, "cache flush denied", regs, error_code, NULL); } } diff -urN linux-a1/arch/i386/kernel/vm86.c linux-b1/arch/i386/kernel/vm86.c --- linux-a1/arch/i386/kernel/vm86.c Sat Jan 11 03:25:01 2003 +++ linux-b1/arch/i386/kernel/vm86.c Sat Jan 11 03:30:22 2003 @@ -502,6 +502,21 @@ int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno) { + switch(trapno) { + case 13: + case 19: + handle_vm86_fault(regs, error_code); + return 0; + case 0: + case 1: + case 3: + case 4: + case 7: + break; + default: + return 1; + }; + if (VMPI.is_vm86pus) { if ( (trapno==3) || (trapno==1) ) return_to_32bit(regs, VM86_TRAP + (trapno << 8));

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