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-rw-r--r--arch/arm64/include/asm/efi.h8
-rw-r--r--arch/arm64/kernel/efi-rt-wrapper.S33
-rw-r--r--arch/arm64/kernel/efi.c26
-rw-r--r--arch/arm64/mm/fault.c4
-rw-r--r--drivers/firmware/efi/efi.c2
-rw-r--r--drivers/firmware/efi/libstub/random.c7
-rw-r--r--drivers/firmware/efi/tpm.c2
-rw-r--r--drivers/firmware/efi/vars.c68
-rw-r--r--include/linux/efi.h2
9 files changed, 98 insertions, 54 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 439e2bc5d5d8..d6cf535d8352 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -14,8 +14,16 @@
#ifdef CONFIG_EFI
extern void efi_init(void);
+
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);
#else
#define efi_init()
+
+static inline
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
+{
+ return false;
+}
#endif
int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S
index 75691a2641c1..67babd5f04c2 100644
--- a/arch/arm64/kernel/efi-rt-wrapper.S
+++ b/arch/arm64/kernel/efi-rt-wrapper.S
@@ -6,7 +6,7 @@
#include <linux/linkage.h>
SYM_FUNC_START(__efi_rt_asm_wrapper)
- stp x29, x30, [sp, #-32]!
+ stp x29, x30, [sp, #-112]!
mov x29, sp
/*
@@ -17,6 +17,20 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
stp x1, x18, [sp, #16]
/*
+ * Preserve all callee saved registers and record the stack pointer
+ * value in a per-CPU variable so we can recover from synchronous
+ * exceptions occurring while running the firmware routines.
+ */
+ stp x19, x20, [sp, #32]
+ stp x21, x22, [sp, #48]
+ stp x23, x24, [sp, #64]
+ stp x25, x26, [sp, #80]
+ stp x27, x28, [sp, #96]
+
+ adr_this_cpu x8, __efi_rt_asm_recover_sp, x9
+ str x29, [x8]
+
+ /*
* We are lucky enough that no EFI runtime services take more than
* 5 arguments, so all are passed in registers rather than via the
* stack.
@@ -31,7 +45,7 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
ldp x1, x2, [sp, #16]
cmp x2, x18
- ldp x29, x30, [sp], #32
+ ldp x29, x30, [sp], #112
b.ne 0f
ret
0:
@@ -45,3 +59,18 @@ SYM_FUNC_START(__efi_rt_asm_wrapper)
mov x18, x2
b efi_handle_corrupted_x18 // tail call
SYM_FUNC_END(__efi_rt_asm_wrapper)
+
+SYM_FUNC_START(__efi_rt_asm_recover)
+ ldr_this_cpu x8, __efi_rt_asm_recover_sp, x9
+ mov sp, x8
+
+ ldp x0, x18, [sp, #16]
+ ldp x19, x20, [sp, #32]
+ ldp x21, x22, [sp, #48]
+ ldp x23, x24, [sp, #64]
+ ldp x25, x26, [sp, #80]
+ ldp x27, x28, [sp, #96]
+ ldp x29, x30, [sp], #112
+
+ b efi_handle_runtime_exception
+SYM_FUNC_END(__efi_rt_asm_recover)
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index e1be6c429810..8d36e66a6e64 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -9,6 +9,7 @@
#include <linux/efi.h>
#include <linux/init.h>
+#include <linux/percpu.h>
#include <asm/efi.h>
@@ -128,3 +129,28 @@ asmlinkage efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f)
pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
return s;
}
+
+asmlinkage DEFINE_PER_CPU(u64, __efi_rt_asm_recover_sp);
+
+asmlinkage efi_status_t __efi_rt_asm_recover(void);
+
+asmlinkage efi_status_t efi_handle_runtime_exception(const char *f)
+{
+ pr_err(FW_BUG "Synchronous exception occurred in EFI runtime service %s()\n", f);
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return EFI_ABORTED;
+}
+
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
+{
+ /* Check whether the exception occurred while running the firmware */
+ if (current_work() != &efi_rts_work.work || regs->pc >= TASK_SIZE_64)
+ return false;
+
+ pr_err(FW_BUG "Unable to handle %s in EFI runtime service\n", msg);
+ add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
+ dump_stack();
+
+ regs->pc = (u64)__efi_rt_asm_recover;
+ return true;
+}
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 5b391490e045..3e9cf9826417 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -30,6 +30,7 @@
#include <asm/bug.h>
#include <asm/cmpxchg.h>
#include <asm/cpufeature.h>
+#include <asm/efi.h>
#include <asm/exception.h>
#include <asm/daifflags.h>
#include <asm/debug-monitors.h>
@@ -391,6 +392,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned long esr,
msg = "paging request";
}
+ if (efi_runtime_fixup_exception(regs, msg))
+ return;
+
die_kernel_fault(msg, addr, esr, regs);
}
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3ecdc43a3f2b..a46df5d1d094 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -611,7 +611,7 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
seed = early_memremap(efi_rng_seed, sizeof(*seed));
if (seed != NULL) {
- size = READ_ONCE(seed->size);
+ size = min(seed->size, EFI_RANDOM_SEED_SIZE);
early_memunmap(seed, sizeof(*seed));
} else {
pr_err("Could not map UEFI random seed!\n");
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index 24aa37535372..33ab56769595 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -75,7 +75,12 @@ efi_status_t efi_random_get_seed(void)
if (status != EFI_SUCCESS)
return status;
- status = efi_bs_call(allocate_pool, EFI_RUNTIME_SERVICES_DATA,
+ /*
+ * Use EFI_ACPI_RECLAIM_MEMORY here so that it is guaranteed that the
+ * allocation will survive a kexec reboot (although we refresh the seed
+ * beforehand)
+ */
+ status = efi_bs_call(allocate_pool, EFI_ACPI_RECLAIM_MEMORY,
sizeof(*seed) + EFI_RANDOM_SEED_SIZE,
(void **)&seed);
if (status != EFI_SUCCESS)
diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
index 8f665678e9e3..e8d69bd548f3 100644
--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -97,7 +97,7 @@ int __init efi_tpm_eventlog_init(void)
goto out_calc;
}
- memblock_reserve((unsigned long)final_tbl,
+ memblock_reserve(efi.tpm_final_log,
tbl_size + sizeof(*final_tbl));
efi_tpm_final_log_size = tbl_size;
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 433b61587139..0ba9f18312f5 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -21,29 +21,22 @@ static struct efivars *__efivars;
static DEFINE_SEMAPHORE(efivars_lock);
-static efi_status_t check_var_size(u32 attributes, unsigned long size)
-{
- const struct efivar_operations *fops;
-
- fops = __efivars->ops;
-
- if (!fops->query_variable_store)
- return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES;
-
- return fops->query_variable_store(attributes, size, false);
-}
-
-static
-efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size)
+static efi_status_t check_var_size(bool nonblocking, u32 attributes,
+ unsigned long size)
{
const struct efivar_operations *fops;
+ efi_status_t status;
fops = __efivars->ops;
if (!fops->query_variable_store)
+ status = EFI_UNSUPPORTED;
+ else
+ status = fops->query_variable_store(attributes, size,
+ nonblocking);
+ if (status == EFI_UNSUPPORTED)
return (size <= SZ_64K) ? EFI_SUCCESS : EFI_OUT_OF_RESOURCES;
-
- return fops->query_variable_store(attributes, size, true);
+ return status;
}
/**
@@ -196,26 +189,6 @@ efi_status_t efivar_get_next_variable(unsigned long *name_size,
EXPORT_SYMBOL_NS_GPL(efivar_get_next_variable, EFIVAR);
/*
- * efivar_set_variable_blocking() - local helper function for set_variable
- *
- * Must be called with efivars_lock held.
- */
-static efi_status_t
-efivar_set_variable_blocking(efi_char16_t *name, efi_guid_t *vendor,
- u32 attr, unsigned long data_size, void *data)
-{
- efi_status_t status;
-
- if (data_size > 0) {
- status = check_var_size(attr, data_size +
- ucs2_strsize(name, 1024));
- if (status != EFI_SUCCESS)
- return status;
- }
- return __efivars->ops->set_variable(name, vendor, attr, data_size, data);
-}
-
-/*
* efivar_set_variable_locked() - set a variable identified by name/vendor
*
* Must be called with efivars_lock held. If @nonblocking is set, it will use
@@ -228,23 +201,21 @@ efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor,
efi_set_variable_t *setvar;
efi_status_t status;
- if (!nonblocking)
- return efivar_set_variable_blocking(name, vendor, attr,
- data_size, data);
+ if (data_size > 0) {
+ status = check_var_size(nonblocking, attr,
+ data_size + ucs2_strsize(name, 1024));
+ if (status != EFI_SUCCESS)
+ return status;
+ }
/*
* If no _nonblocking variant exists, the ordinary one
* is assumed to be non-blocking.
*/
- setvar = __efivars->ops->set_variable_nonblocking ?:
- __efivars->ops->set_variable;
+ setvar = __efivars->ops->set_variable_nonblocking;
+ if (!setvar || !nonblocking)
+ setvar = __efivars->ops->set_variable;
- if (data_size > 0) {
- status = check_var_size_nonblocking(attr, data_size +
- ucs2_strsize(name, 1024));
- if (status != EFI_SUCCESS)
- return status;
- }
return setvar(name, vendor, attr, data_size, data);
}
EXPORT_SYMBOL_NS_GPL(efivar_set_variable_locked, EFIVAR);
@@ -264,7 +235,8 @@ efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor,
if (efivar_lock())
return EFI_ABORTED;
- status = efivar_set_variable_blocking(name, vendor, attr, data_size, data);
+ status = efivar_set_variable_locked(name, vendor, attr, data_size,
+ data, false);
efivar_unlock();
return status;
}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 80f3c1c7827d..929d559ad41d 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1222,7 +1222,7 @@ efi_status_t efi_random_get_seed(void);
arch_efi_call_virt_teardown(); \
})
-#define EFI_RANDOM_SEED_SIZE 64U
+#define EFI_RANDOM_SEED_SIZE 32U // BLAKE2S_HASH_SIZE
struct linux_efi_random_seed {
u32 size;
generated by cgit v1.2.3-70-g09d2 (git 2.48.1) at 2025-03-10 07:34:51 +0000