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authorArd Biesheuvel <ardb@kernel.org>2023-10-20 19:11:06 +0300
committerArd Biesheuvel <ardb@kernel.org>2023-10-20 19:11:06 +0300
commitc03d21f05e76b25f907684bdf874308dcefab385 (patch)
tree329af17330383296b4d68102ac6a474da480571f
parent8dbe33956d96c9d066ef15ca933ede30748198b2 (diff)
parent50e782a86c980d4f8292ef82ed8139282ca07a98 (diff)
downloadlinux-c03d21f05e76b25f907684bdf874308dcefab385.tar.xz
Merge 3rd batch of EFI fixes into efi/urgent
-rw-r--r--drivers/firmware/efi/efi.c8
-rw-r--r--drivers/firmware/efi/libstub/x86-stub.c7
-rw-r--r--drivers/firmware/efi/libstub/x86-stub.h2
-rw-r--r--drivers/firmware/efi/unaccepted_memory.c64
4 files changed, 71 insertions, 10 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index ce20a60676f0..1974f0ad32ba 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -273,9 +273,13 @@ static __init int efivar_ssdt_load(void)
if (status == EFI_NOT_FOUND) {
break;
} else if (status == EFI_BUFFER_TOO_SMALL) {
- name = krealloc(name, name_size, GFP_KERNEL);
- if (!name)
+ efi_char16_t *name_tmp =
+ krealloc(name, name_size, GFP_KERNEL);
+ if (!name_tmp) {
+ kfree(name);
return -ENOMEM;
+ }
+ name = name_tmp;
continue;
}
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 2fee52ed335d..9d5df683f882 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -605,11 +605,8 @@ setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_s
break;
case EFI_UNACCEPTED_MEMORY:
- if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY)) {
- efi_warn_once(
-"The system has unaccepted memory, but kernel does not support it\nConsider enabling CONFIG_UNACCEPTED_MEMORY\n");
+ if (!IS_ENABLED(CONFIG_UNACCEPTED_MEMORY))
continue;
- }
e820_type = E820_TYPE_RAM;
process_unaccepted_memory(d->phys_addr,
d->phys_addr + PAGE_SIZE * d->num_pages);
@@ -852,6 +849,8 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
unsigned long kernel_entry;
efi_status_t status;
+ boot_params_pointer = boot_params;
+
efi_system_table = sys_table_arg;
/* Check if we were booted by the EFI firmware */
if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
diff --git a/drivers/firmware/efi/libstub/x86-stub.h b/drivers/firmware/efi/libstub/x86-stub.h
index 37c5a36b9d8c..2748bca192df 100644
--- a/drivers/firmware/efi/libstub/x86-stub.h
+++ b/drivers/firmware/efi/libstub/x86-stub.h
@@ -2,6 +2,8 @@
#include <linux/efi.h>
+extern struct boot_params *boot_params_pointer asm("boot_params");
+
extern void trampoline_32bit_src(void *, bool);
extern const u16 trampoline_ljmp_imm_offset;
diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c
index 853f7dc3c21d..135278ddaf62 100644
--- a/drivers/firmware/efi/unaccepted_memory.c
+++ b/drivers/firmware/efi/unaccepted_memory.c
@@ -5,9 +5,17 @@
#include <linux/spinlock.h>
#include <asm/unaccepted_memory.h>
-/* Protects unaccepted memory bitmap */
+/* Protects unaccepted memory bitmap and accepting_list */
static DEFINE_SPINLOCK(unaccepted_memory_lock);
+struct accept_range {
+ struct list_head list;
+ unsigned long start;
+ unsigned long end;
+};
+
+static LIST_HEAD(accepting_list);
+
/*
* accept_memory() -- Consult bitmap and accept the memory if needed.
*
@@ -24,6 +32,7 @@ void accept_memory(phys_addr_t start, phys_addr_t end)
{
struct efi_unaccepted_memory *unaccepted;
unsigned long range_start, range_end;
+ struct accept_range range, *entry;
unsigned long flags;
u64 unit_size;
@@ -78,20 +87,67 @@ void accept_memory(phys_addr_t start, phys_addr_t end)
if (end > unaccepted->size * unit_size * BITS_PER_BYTE)
end = unaccepted->size * unit_size * BITS_PER_BYTE;
- range_start = start / unit_size;
-
+ range.start = start / unit_size;
+ range.end = DIV_ROUND_UP(end, unit_size);
+retry:
spin_lock_irqsave(&unaccepted_memory_lock, flags);
+
+ /*
+ * Check if anybody works on accepting the same range of the memory.
+ *
+ * The check is done with unit_size granularity. It is crucial to catch
+ * all accept requests to the same unit_size block, even if they don't
+ * overlap on physical address level.
+ */
+ list_for_each_entry(entry, &accepting_list, list) {
+ if (entry->end < range.start)
+ continue;
+ if (entry->start >= range.end)
+ continue;
+
+ /*
+ * Somebody else accepting the range. Or at least part of it.
+ *
+ * Drop the lock and retry until it is complete.
+ */
+ spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
+ goto retry;
+ }
+
+ /*
+ * Register that the range is about to be accepted.
+ * Make sure nobody else will accept it.
+ */
+ list_add(&range.list, &accepting_list);
+
+ range_start = range.start;
for_each_set_bitrange_from(range_start, range_end, unaccepted->bitmap,
- DIV_ROUND_UP(end, unit_size)) {
+ range.end) {
unsigned long phys_start, phys_end;
unsigned long len = range_end - range_start;
phys_start = range_start * unit_size + unaccepted->phys_base;
phys_end = range_end * unit_size + unaccepted->phys_base;
+ /*
+ * Keep interrupts disabled until the accept operation is
+ * complete in order to prevent deadlocks.
+ *
+ * Enabling interrupts before calling arch_accept_memory()
+ * creates an opportunity for an interrupt handler to request
+ * acceptance for the same memory. The handler will continuously
+ * spin with interrupts disabled, preventing other task from
+ * making progress with the acceptance process.
+ */
+ spin_unlock(&unaccepted_memory_lock);
+
arch_accept_memory(phys_start, phys_end);
+
+ spin_lock(&unaccepted_memory_lock);
bitmap_clear(unaccepted->bitmap, range_start, len);
}
+
+ list_del(&range.list);
spin_unlock_irqrestore(&unaccepted_memory_lock, flags);
}