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arch: x86: workaround for EFI call return with interrupt enabled

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The EFI console output call return with interrput enabled, it is a
firmware bug. And there was a solution that disabled interrupt it
return right away. But in some case the interrupt could happen
during the efi call context. If an interrupt was handled, a printk
call again will make it re-entried, or a swap might be happens.
This is suggested solution appiled for EFI console output:

1. Skip printk call when it is called in interrupt context.
2. Disable the schedule during the EFI call window.

Signed-off-by: Enjia Mai <enjia.mai@intel.com>
This commit is contained in:
Enjia Mai 2022-07-04 17:36:49 +08:00 • committed by Christopher Friedt
commit 05147693ca
1 changed files with 18 additions and 0 deletions
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18
arch/x86/core/efi.c
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@ -8,6 +8,8 @@
#include <zephyr/arch/x86/efi.h>
#include <zephyr/sys/mem_manage.h>
#include "../zefi/efi.h" /* ZEFI not on include path */
#include <zephyr/kernel.h>
#include <kernel_arch_func.h>
#define EFI_CON_BUFSZ 128
@ -86,6 +88,12 @@ static uint64_t efi_call(void *fn, uint64_t arg1, uint64_t arg2)
{
void *stack_top = &efi_stack[ARRAY_SIZE(efi_stack) - 4];
/* During the efi_call window the interrupt is enabled, that
* means an interrupt could happen and trigger scheduler at
* end of the interrupt. Try to prevent swap happening.
*/
k_sched_lock();
__asm__ volatile("movq %%cr3, %%r12;" /* save zephyr page table */
"movq %%rsp, %%r13;" /* save stack pointer */
"movq %%rsi, %%rsp;" /* set stack */
@ -98,6 +106,7 @@ static uint64_t efi_call(void *fn, uint64_t arg1, uint64_t arg2)
: "c"(arg1), "d"(arg2), "S"(stack_top), "D"(efi->efi_cr3)
: "r8", "r9", "r10", "r11", "r12", "r13");
k_sched_unlock();
return (uint64_t) fn;
}
@ -110,6 +119,15 @@ int efi_console_putchar(int c)
static void *output_string_fn;
struct efi_system_table *efist = efi->efi_systab;
/* Limit the printk call in interrupt context for
* EFI cosnsole. This is a workaround that prevents
* the printk call re-entries when an interrupt
* happens during the EFI call window.
*/
if (arch_is_in_isr()) {
return 0;
}
if (c == '\n') {
efi_console_putchar('\r');
}