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efi_loader: add checking for incorrect use of EFI_ENTRY/EXIT

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Missing an EFI_ENTRY() or doubling up EFI_EXIT() leads to non-obvious
crashes.  Let's add some error checking.

Signed-off-by: Rob Clark <robdclark@gmail.com>
[agraf: fix bogus assert() and fix app_gd breakage]
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Rob Clark 2017-07-27 08:04:18 -04:00 committed by Alexander Graf
parent a095aadffa
commit c160d2f5ec
2 changed files with 41 additions and 21 deletions
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17
include/efi_loader.h
View File

@ -15,11 +15,14 @@
#include <linux/list.h>
int __efi_entry_check(void);
int __efi_exit_check(void);
/*
* Enter the u-boot world from UEFI:
*/
#define EFI_ENTRY(format, ...) do { \
efi_restore_gd(); \
assert(__efi_entry_check()); \
debug("EFI: Entry %s(" format ")\n", __func__, ##__VA_ARGS__); \
} while(0)
@ -29,7 +32,8 @@
#define EFI_EXIT(ret) ({ \
efi_status_t _r = ret; \
debug("EFI: Exit: %s: %u\n", __func__, (u32)(_r & ~EFI_ERROR_MASK)); \
efi_exit_func(_r); \
assert(__efi_exit_check()); \
_r; \
})
/*
@ -37,9 +41,9 @@
*/
#define EFI_CALL(exp) do { \
debug("EFI: Call: %s\n", #exp); \
efi_exit_func(EFI_SUCCESS); \
assert(__efi_exit_check()); \
exp; \
efi_restore_gd(); \
assert(__efi_entry_check()); \
debug("EFI: Return From: %s\n", #exp); \
} while(0)
@ -139,10 +143,9 @@ void efi_timer_check(void);
void *efi_load_pe(void *efi, struct efi_loaded_image *loaded_image_info);
/* Called once to store the pristine gd pointer */
void efi_save_gd(void);
/* Called from EFI_ENTRY on callback entry to put gd into the gd register */
/* Special case handler for error/abort that just tries to dtrt to get
* back to u-boot world */
void efi_restore_gd(void);
/* Called from EFI_EXIT on callback exit to restore the gd register */
efi_status_t efi_exit_func(efi_status_t ret);
/* Call this to relocate the runtime section to an address space */
void efi_runtime_relocate(ulong offset, struct efi_mem_desc *map);
/* Call this to set the current device name */

45
lib/efi_loader/efi_boottime.c
View File

@ -49,6 +49,30 @@ static struct efi_configuration_table __efi_runtime_data efi_conf_table[2];
static volatile void *efi_gd, *app_gd;
#endif
static int entry_count;
/* Called on every callback entry */
int __efi_entry_check(void)
{
int ret = entry_count++ == 0;
#ifdef CONFIG_ARM
assert(efi_gd);
app_gd = gd;
gd = efi_gd;
#endif
return ret;
}
/* Called on every callback exit */
int __efi_exit_check(void)
{
int ret = --entry_count == 0;
#ifdef CONFIG_ARM
gd = app_gd;
#endif
return ret;
}
/* Called from do_bootefi_exec() */
void efi_save_gd(void)
{
@ -57,30 +81,21 @@ void efi_save_gd(void)
#endif
}
/* Called on every callback entry */
/*
* Special case handler for error/abort that just forces things back
* to u-boot world so we can dump out an abort msg, without any care
* about returning back to UEFI world.
*/
void efi_restore_gd(void)
{
#ifdef CONFIG_ARM
/* Only restore if we're already in EFI context */
if (!efi_gd)
return;
if (gd != efi_gd)
app_gd = gd;
gd = efi_gd;
#endif
}
/* Called on every callback exit */
efi_status_t efi_exit_func(efi_status_t ret)
{
#ifdef CONFIG_ARM
gd = app_gd;
#endif
return ret;
}
/* Low 32 bit */
#define EFI_LOW32(a) (a & 0xFFFFFFFFULL)
/* High 32 bit */
@ -733,7 +748,9 @@ static efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
return EFI_EXIT(info->exit_status);
}
__efi_exit_check();
entry(image_handle, &systab);
__efi_entry_check();
/* Should usually never get here */
return EFI_EXIT(EFI_SUCCESS);