efi/libstub: Implement printk-style logging

Use the efi_printk function in efi_info/efi_err, and add efi_debug. This
allows formatted output at different log levels.

Add the notion of a loglevel instead of just quiet/not-quiet, and
parse the efi=debug kernel parameter in addition to quiet.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200520170223.GA3333632@rani.riverdale.lan/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Arvind Sankar
2020-05-20 19:07:54 +02:00
committed by Ard Biesheuvel
parent 8fb331e10b
commit 23d5b73fbf
2 changed files with 35 additions and 8 deletions

View File

@@ -11,6 +11,7 @@
#include <linux/efi.h>
#include <linux/kernel.h>
#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
#include <asm/efi.h>
#include "efistub.h"
@@ -18,7 +19,7 @@
bool efi_nochunk;
bool efi_nokaslr;
bool efi_noinitrd;
bool efi_quiet;
int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
bool efi_novamap;
static bool efi_nosoftreserve;
@@ -58,6 +59,28 @@ int efi_printk(const char *fmt, ...)
char printf_buf[256];
va_list args;
int printed;
int loglevel = printk_get_level(fmt);
switch (loglevel) {
case '0' ... '9':
loglevel -= '0';
break;
default:
/*
* Use loglevel -1 for cases where we just want to print to
* the screen.
*/
loglevel = -1;
break;
}
if (loglevel >= efi_loglevel)
return 0;
if (loglevel >= 0)
efi_puts("EFI stub: ");
fmt = printk_skip_level(fmt);
va_start(args, fmt);
printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
@@ -100,7 +123,7 @@ efi_status_t efi_parse_options(char const *cmdline)
if (!strcmp(param, "nokaslr")) {
efi_nokaslr = true;
} else if (!strcmp(param, "quiet")) {
efi_quiet = true;
efi_loglevel = CONSOLE_LOGLEVEL_QUIET;
} else if (!strcmp(param, "noinitrd")) {
efi_noinitrd = true;
} else if (!strcmp(param, "efi") && val) {
@@ -114,6 +137,8 @@ efi_status_t efi_parse_options(char const *cmdline)
efi_disable_pci_dma = true;
if (parse_option_str(val, "no_disable_early_pci_dma"))
efi_disable_pci_dma = false;
if (parse_option_str(val, "debug"))
efi_loglevel = CONSOLE_LOGLEVEL_DEBUG;
} else if (!strcmp(param, "video") &&
val && strstarts(val, "efifb:")) {
efi_parse_option_graphics(val + strlen("efifb:"));