If exception with error code is handled by task gate, error code should
be pushed to new task stack.
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
---
x86/taskswitch2.c | 39 +++++++++++++++++++++++++++++++++++++++
1 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/x86/taskswitch2.c b/x86/taskswitch2.c
index f51cb91..683834e 100644
--- a/x86/taskswitch2.c
+++ b/x86/taskswitch2.c
@@ -3,6 +3,7 @@
#include "apic-defs.h"
#include "apic.h"
#include "processor.h"
+#include "vm.h"
#define xstr(s) str(s)
#define str(s) #s
@@ -10,6 +11,9 @@
static volatile int test_count;
static volatile unsigned int test_divider;
+static char *fault_addr;
+static ulong fault_phys;
+
static int g_fail;
static int g_tests;
@@ -66,6 +70,27 @@ start:
goto start;
}
+void do_pf_tss(ulong *error_code)
+{
+ printf("PF task is running %x %x\n", error_code, *(ulong*)error_code);
+ print_current_tss_info();
+ if (*(ulong*)error_code == 0x2) /* write access, not present */
+ test_count++;
+ install_pte(phys_to_virt(read_cr3()), 1, fault_addr,
+ fault_phys | PTE_PRESENT | PTE_WRITE, 0);
+}
+
+extern void pf_tss(void);
+
+asm (
+ "pf_tss: \n\t"
+ "push %esp \n\t"
+ "call do_pf_tss \n\t"
+ "add $4, %esp \n\t"
+ "iret\n\t"
+ "jmp pf_tss\n\t"
+ );
+
static void jmp_tss(void)
{
start:
@@ -92,6 +117,7 @@ int main()
{
unsigned int res;
+ setup_vm();
setup_idt();
setup_gdt();
setup_tss32();
@@ -156,6 +182,19 @@ int main()
printf("Return from int 3\n");
report("BP exeption", test_count == 1);
+ /*
+ * test that PF triggers task gate and error code is placed on
+ * exception task's stack
+ */
+ fault_addr = alloc_vpage();
+ fault_phys = (ulong)virt_to_phys(alloc_page());
+ test_count = 0;
+ set_intr_task_gate(14, pf_tss);
+ printf("Access unmapped page\n");
+ *fault_addr = 0;
+ printf("Return from pf tss\n");
+ report("PF exeption", test_count == 1);
+
/* test that calling a task by lcall works */
test_count = 0;
set_intr_task_gate(0, irq_tss);
--
1.7.2.3
--
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