diff options
| author | Luca Dariz <luca@orpolo.org> | 2023-07-29 19:45:14 +0200 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2023-08-04 23:34:18 +0200 |
| commit | 8b29b18fda413928c32473475ca51aa05c52db18 (patch) | |
| tree | e3dca31b5321ae00d7c88b5dc6a78161622fcbeb /x86_64 | |
| parent | bdcafee412ab6eec58f6b315e16e57fe3dad002f (diff) | |
x86_64: install emergency handler for double fault
* i386/i386/idt.c: add selector for the interrupt-specific stack
* i386/i386/ktss.c: configure ist1 to use a dedicated stack
* i386/i386/trap.c: add double fault handler, which just prints the
state and panics. There is not much else to do in this case but it's
useful for troubleshooting
* x86_64/idt_inittab.S: allow to specify an interrupt stack for custom
handlers
* x86_64/locore.S: add double fault handler
Message-Id: <20230729174514.1145656-1-luca@orpolo.org>
Diffstat (limited to 'x86_64')
| -rw-r--r-- | x86_64/idt_inittab.S | 25 | ||||
| -rw-r--r-- | x86_64/locore.S | 15 |
2 files changed, 28 insertions, 12 deletions
diff --git a/x86_64/idt_inittab.S b/x86_64/idt_inittab.S index f021b56d..fc1df0c7 100644 --- a/x86_64/idt_inittab.S +++ b/x86_64/idt_inittab.S @@ -50,12 +50,13 @@ ENTRY(idt_inittab) .quad entry ;\ .text #else /* MACH_PV_DESCRIPTORS */ -#define IDT_ENTRY(n,entry,type) \ +#define IDT_ENTRY(n,entry,type,ist) \ .data 2 ;\ .quad entry ;\ .word n ;\ .word type ;\ - .long 0 /*pad*/ ;\ + .word ist ;\ + .word 0 /*pad*/ ;\ .text #endif /* MACH_PV_DESCRIPTORS */ @@ -63,7 +64,7 @@ ENTRY(idt_inittab) * No error code. Clear error code and push trap number. */ #define EXCEPTION(n,name) \ - IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_TRAP_GATE);\ + IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_TRAP_GATE, 0);\ ENTRY(name) ;\ INT_FIX ;\ pushq $(0) ;\ @@ -74,7 +75,7 @@ ENTRY(name) ;\ * User-accessible exception. Otherwise, same as above. */ #define EXCEP_USR(n,name) \ - IDT_ENTRY(n,EXT(name),ACC_PL_U|ACC_TRAP_GATE);\ + IDT_ENTRY(n,EXT(name),ACC_PL_U|ACC_TRAP_GATE, 0);\ ENTRY(name) ;\ INT_FIX ;\ pushq $(0) ;\ @@ -85,7 +86,7 @@ ENTRY(name) ;\ * Error code has been pushed. Just push trap number. */ #define EXCEP_ERR(n,name) \ - IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_INTR_GATE);\ + IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_INTR_GATE, 0);\ ENTRY(name) ;\ INT_FIX ;\ pushq $(n) ;\ @@ -95,25 +96,25 @@ ENTRY(name) ;\ * Special interrupt code: dispatches to a unique entrypoint, * not defined automatically here. */ -#define EXCEP_SPC(n,name) \ - IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_TRAP_GATE) +#define EXCEP_SPC(n,name, ist) \ + IDT_ENTRY(n,EXT(name),ACC_PL_K|ACC_TRAP_GATE, ist) EXCEPTION(0x00,t_zero_div) -EXCEP_SPC(0x01,t_debug) +EXCEP_SPC(0x01,t_debug, 0) /* skip NMI interrupt - let more specific code figure that out. */ EXCEP_USR(0x03,t_int3) EXCEP_USR(0x04,t_into) EXCEP_USR(0x05,t_bounds) EXCEPTION(0x06,t_invop) EXCEPTION(0x07,t_nofpu) -EXCEPTION(0x08,a_dbl_fault) +EXCEP_SPC(0x08,t_dbl_fault, 1) EXCEPTION(0x09,a_fpu_over) EXCEPTION(0x0a,a_inv_tss) -EXCEP_SPC(0x0b,t_segnp) +EXCEP_SPC(0x0b,t_segnp, 0) EXCEP_ERR(0x0c,t_stack_fault) -EXCEP_SPC(0x0d,t_gen_prot) -EXCEP_SPC(0x0e,t_page_fault) +EXCEP_SPC(0x0d,t_gen_prot, 0) +EXCEP_SPC(0x0e,t_page_fault, 0) #ifdef MACH_PV_DESCRIPTORS EXCEP_ERR(0x0f,t_trap_0f) #else diff --git a/x86_64/locore.S b/x86_64/locore.S index 2938e430..16b0dde5 100644 --- a/x86_64/locore.S +++ b/x86_64/locore.S @@ -345,6 +345,21 @@ ENTRY(start_timer) * */ +/* Try to save/show some information when a double fault happens + * We can't recover to a working state, so if we have a debugger wait for it, + * otherwise reset */ +ENTRY(t_dbl_fault) + INT_FIX + cli /* disable interrupts that might corrupt the state*/ + pusha + movq %cr2,%rax + movq %rax,R_CR2-R_R15(%rsp) /* CR2 might contain the faulting address */ + subq $48,%rsp // FIXME remove when segments are cleaned up + movq %rsp,%rdi /* pass the saved state */ + call handle_double_fault + jmp cpu_shutdown /* reset */ +END(t_dbl_fault) + /* * General protection or segment-not-present fault. * Check for a GP/NP fault in the kernel_return |