diff options
| author | Felix Held <felix-coreboot@felixheld.de> | 2023-08-12 00:30:36 +0200 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2023-08-15 14:45:20 +0000 |
| commit | 38880d236fd97e3bdf61234363bc4cd7e9869870 (patch) | |
| tree | 877e33dcdead83939b9c2219d33868f71eb1db35 /src/device/oprom/realmode | |
| parent | 6e039076ab106a11ec9f82ef2f8250b20f1a885e (diff) | |
device/oprom/realmode/x86: temporary disable NULL breakpoints
Disable NULL breakpoints in setup_realmode_idt before calling
write_idt_stub in a loop.
TEST=No more spurious Null dereference errors in the console output.
Before Mandolin showed these two errors before running the VBIOS:
[ERROR] Null dereference at eip: 0x4e6f1a35
[ERROR] Null dereference at eip: 0x4e6f1a4f
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I2255d85030e41192ae8a3a7f0f6576c0d373eead
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77172
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Diffstat (limited to 'src/device/oprom/realmode')
| -rw-r--r-- | src/device/oprom/realmode/x86.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/device/oprom/realmode/x86.c b/src/device/oprom/realmode/x86.c index 7972011a3f..367614db2b 100644 --- a/src/device/oprom/realmode/x86.c +++ b/src/device/oprom/realmode/x86.c @@ -2,6 +2,7 @@ #include <device/mmio.h> #include <arch/interrupt.h> +#include <arch/null_breakpoint.h> #include <arch/registers.h> #include <boot/coreboot_tables.h> #include <console/console.h> @@ -178,15 +179,21 @@ static void setup_realmode_idt(void) struct realmode_idt *idts = (struct realmode_idt *) 0; int i; + /* It's expected that we write to the NULL page in the first two iterations of the + following loop, so temporarily disable the NULL breakpoint. */ + null_breakpoint_disable(); + /* Copy IDT stub code for each interrupt. This might seem wasteful * but it is really simple */ - for (i = 0; i < 256; i++) { + for (i = 0; i < 256; i++) { idts[i].cs = 0; idts[i].offset = 0x1000 + (i * __idt_handler_size); write_idt_stub((void *)((uintptr_t)idts[i].offset), i); } + null_breakpoint_init(); + /* Many option ROMs use the hard coded interrupt entry points in the * system bios. So install them at the known locations. */ |