Provide easy way for test to hook its own exception handler.
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
---
lib/x86/desc.c | 122 +++++++++++++++++++++++++++++++++++++++----------------
lib/x86/desc.h | 15 +++++++
2 files changed, 101 insertions(+), 36 deletions(-)
diff --git a/lib/x86/desc.c b/lib/x86/desc.c
index aa0b4f4..0da8989 100644
--- a/lib/x86/desc.c
+++ b/lib/x86/desc.c
@@ -90,19 +90,6 @@ void set_idt_entry(int vec, void *addr, int dpl)
#endif
}
-struct ex_regs {
- unsigned long rax, rcx, rdx, rbx;
- unsigned long dummy, rbp, rsi, rdi;
-#ifdef __x86_64__
- unsigned long r8, r9, r10, r11;
- unsigned long r12, r13, r14, r15;
-#endif
- unsigned long vector;
- unsigned long error_code;
- unsigned long rip;
- unsigned long cs;
- unsigned long rflags;
-};
struct ex_record {
unsigned long rip;
@@ -111,10 +98,7 @@ struct ex_record {
extern struct ex_record exception_table_start, exception_table_end;
-#ifndef __x86_64__
-__attribute__((regparm(1)))
-#endif
-void do_handle_exception(struct ex_regs *regs)
+static void check_exception_table(struct ex_regs *regs)
{
struct ex_record *ex;
unsigned ex_val;
@@ -129,10 +113,34 @@ void do_handle_exception(struct ex_regs *regs)
return;
}
}
- printf("unhandled excecption\n");
+ printf("unhandled excecption %d\n", regs->vector);
exit(7);
}
+static void (*exception_handlers[32])(struct ex_regs *regs);
+
+
+void handle_exception(u8 v, void (*func)(struct ex_regs *regs))
+{
+ if (v < 32)
+ exception_handlers[v] = func;
+}
+
+#ifndef __x86_64__
+__attribute__((regparm(1)))
+#endif
+void do_handle_exception(struct ex_regs *regs)
+{
+ if (regs->vector < 32 && exception_handlers[regs->vector]) {
+ exception_handlers[regs->vector](regs);
+ return;
+ }
+ printf("unhandled cpu excecption %d\n", regs->vector);
+ if (regs->vector == 14)
+ printf("PF at %p addr %p\n", regs->rip, read_cr2());
+ exit(7);
+}
+
#ifdef __x86_64__
# define R "r"
# define W "q"
@@ -143,22 +151,42 @@ void do_handle_exception(struct ex_regs *regs)
# define S "4"
#endif
-asm (".pushsection .text \n\t"
- "ud_fault: \n\t"
- "push"W" $0 \n\t"
- "push"W" $6 \n\t"
- "jmp handle_exception \n\t"
-
- "gp_fault: \n\t"
- "push"W" $13 \n\t"
- "jmp handle_exception \n\t"
-
- "de_fault: \n\t"
- "push"W" $0 \n\t"
- "push"W" $0 \n\t"
- "jmp handle_exception \n\t"
+#define EX(NAME, N) extern char NAME##_fault; \
+ asm (".pushsection .text \n\t" \
+ #NAME"_fault: \n\t" \
+ "push"W" $0 \n\t" \
+ "push"W" $"#N" \n\t" \
+ "jmp __handle_exception \n\t" \
+ ".popsection")
+
+#define EX_E(NAME, N) extern char NAME##_fault; \
+ asm (".pushsection .text \n\t" \
+ #NAME"_fault: \n\t" \
+ "push"W" $"#N" \n\t" \
+ "jmp __handle_exception \n\t" \
+ ".popsection")
+
+EX(de, 0);
+EX(db, 1);
+EX(nmi, 2);
+EX(bp, 3);
+EX(of, 4);
+EX(br, 5);
+EX(ud, 6);
+EX(nm, 7);
+EX_E(df, 8);
+EX_E(ts, 10);
+EX_E(np, 11);
+EX_E(ss, 12);
+EX_E(gp, 13);
+EX_E(pf, 14);
+EX(mf, 16);
+EX_E(ac, 17);
+EX(mc, 18);
+EX(xm, 19);
- "handle_exception: \n\t"
+asm (".pushsection .text \n\t"
+ "__handle_exception: \n\t"
#ifdef __x86_64__
"push %r15; push %r14; push %r13; push %r12 \n\t"
"push %r11; push %r10; push %r9; push %r8 \n\t"
@@ -182,15 +210,37 @@ asm (".pushsection .text \n\t"
"iret"W" \n\t"
".popsection");
+static void *idt_handlers[32] = {
+ [0] = &de_fault,
+ [1] = &db_fault,
+ [2] = &nmi_fault,
+ [3] = &bp_fault,
+ [4] = &of_fault,
+ [5] = &br_fault,
+ [6] = &ud_fault,
+ [7] = &nm_fault,
+ [8] = &df_fault,
+ [10] = &ts_fault,
+ [11] = &np_fault,
+ [12] = &ss_fault,
+ [13] = &gp_fault,
+ [14] = &pf_fault,
+ [16] = &mf_fault,
+ [17] = &ac_fault,
+ [18] = &mc_fault,
+ [19] = &xm_fault,
+};
void setup_idt(void)
{
- extern char ud_fault, gp_fault, de_fault;
-
+ int i;
load_lidt(idt, 256);
- set_idt_entry(0, &de_fault, 0);
- set_idt_entry(6, &ud_fault, 0);
- set_idt_entry(13, &gp_fault, 0);
+ for (i = 0; i < 32; i++)
+ if (idt_handlers[i])
+ set_idt_entry(i, idt_handlers[i], 0);
+ handle_exception(0, check_exception_table);
+ handle_exception(6, check_exception_table);
+ handle_exception(13, check_exception_table);
}
unsigned exception_vector(void)
diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index 2c9db5b..073878d 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -10,6 +10,20 @@ static inline void setup_gdt(void){}
static inline void setup_tss32(void){}
#endif
+struct ex_regs {
+ unsigned long rax, rcx, rdx, rbx;
+ unsigned long dummy, rbp, rsi, rdi;
+#ifdef __x86_64__
+ unsigned long r8, r9, r10, r11;
+ unsigned long r12, r13, r14, r15;
+#endif
+ unsigned long vector;
+ unsigned long error_code;
+ unsigned long rip;
+ unsigned long cs;
+ unsigned long rflags;
+};
+
#define ASM_TRY(catch) \
"movl $0, %%gs:4 \n\t" \
".pushsection .data.ex \n\t" \
@@ -29,5 +43,6 @@ void set_idt_entry(int vec, void *addr, int dpl);
void set_gdt_entry(int num, u32 base, u32 limit, u8 access, u8 gran);
void set_intr_task_gate(int e, void *fn);
void print_current_tss_info(void);
+void handle_exception(u8 v, void (*func)(struct ex_regs *regs));
#endif
--
1.7.2.3
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
