Merge tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi

Pull EFI updates from Ard Biesheuvel:
 "Another fairly sizable pull request, by EFI subsystem standards.

  Most of the work was done by me, some of it in collaboration with the
  distro and bootloader folks (GRUB, systemd-boot), where the main focus
  has been on removing pointless per-arch differences in the way EFI
  boots a Linux kernel.

   - Refactor the zboot code so that it incorporates all the EFI stub
     logic, rather than calling the decompressed kernel as a EFI app.

   - Add support for initrd= command line option to x86 mixed mode.

   - Allow initrd= to be used with arbitrary EFI accessible file systems
     instead of just the one the kernel itself was loaded from.

   - Move some x86-only handling and manipulation of the EFI memory map
     into arch/x86, as it is not used anywhere else.

   - More flexible handling of any random seeds provided by the boot
     environment (i.e., systemd-boot) so that it becomes available much
     earlier during the boot.

   - Allow improved arch-agnostic EFI support in loaders, by setting a
     uniform baseline of supported features, and adding a generic magic
     number to the DOS/PE header. This should allow loaders such as GRUB
     or systemd-boot to reduce the amount of arch-specific handling
     substantially.

   - (arm64) Run EFI runtime services from a dedicated stack, and use it
     to recover from synchronous exceptions that might occur in the
     firmware code.

   - (arm64) Ensure that we don't allocate memory outside of the 48-bit
     addressable physical range.

   - Make EFI pstore record size configurable

   - Add support for decoding CXL specific CPER records"

* tag 'efi-next-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: (43 commits)
  arm64: efi: Recover from synchronous exceptions occurring in firmware
  arm64: efi: Execute runtime services from a dedicated stack
  arm64: efi: Limit allocations to 48-bit addressable physical region
  efi: Put Linux specific magic number in the DOS header
  efi: libstub: Always enable initrd command line loader and bump version
  efi: stub: use random seed from EFI variable
  efi: vars: prohibit reading random seed variables
  efi: random: combine bootloader provided RNG seed with RNG protocol output
  efi/cper, cxl: Decode CXL Error Log
  efi/cper, cxl: Decode CXL Protocol Error Section
  efi: libstub: fix efi_load_initrd_dev_path() kernel-doc comment
  efi: x86: Move EFI runtime map sysfs code to arch/x86
  efi: runtime-maps: Clarify purpose and enable by default for kexec
  efi: pstore: Add module parameter for setting the record size
  efi: xen: Set EFI_PARAVIRT for Xen dom0 boot on all architectures
  efi: memmap: Move manipulation routines into x86 arch tree
  efi: memmap: Move EFI fake memmap support into x86 arch tree
  efi: libstub: Undeprecate the command line initrd loader
  efi: libstub: Add mixed mode support to command line initrd loader
  efi: libstub: Permit mixed mode return types other than efi_status_t
  ...

1 files changed, 17 insertions, 6 deletions

diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
index 97a9e84840a0..e7b9ec6f8a86 100644
--- a/drivers/firmware/efi/efi-pstore.c
+++ b/drivers/firmware/efi/efi-pstore.c
@@ -10,7 +10,9 @@ MODULE_IMPORT_NS(EFIVAR);
 
 #define DUMP_NAME_LEN 66
 
-#define EFIVARS_DATA_SIZE_MAX 1024
+static unsigned int record_size = 1024;
+module_param(record_size, uint, 0444);
+MODULE_PARM_DESC(record_size, "size of each pstore UEFI var (in bytes, min/default=1024)");
 
 static bool efivars_pstore_disable =
 	IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
@@ -30,7 +32,7 @@ static int efi_pstore_open(struct pstore_info *psi)
 	if (err)
 		return err;
 
-	psi->data = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL);
+	psi->data = kzalloc(record_size, GFP_KERNEL);
 	if (!psi->data)
 		return -ENOMEM;
 
@@ -52,7 +54,7 @@ static inline u64 generic_id(u64 timestamp, unsigned int part, int count)
 static int efi_pstore_read_func(struct pstore_record *record,
 				efi_char16_t *varname)
 {
-	unsigned long wlen, size = EFIVARS_DATA_SIZE_MAX;
+	unsigned long wlen, size = record_size;
 	char name[DUMP_NAME_LEN], data_type;
 	efi_status_t status;
 	int cnt;
@@ -133,7 +135,7 @@ static ssize_t efi_pstore_read(struct pstore_record *record)
 	efi_status_t status;
 
 	for (;;) {
-		varname_size = EFIVARS_DATA_SIZE_MAX;
+		varname_size = 1024;
 
 		/*
 		 * If this is the first read() call in the pstore enumeration,
@@ -224,11 +226,20 @@ static __init int efivars_pstore_init(void)
 	if (efivars_pstore_disable)
 		return 0;
 
-	efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+	/*
+	 * Notice that 1024 is the minimum here to prevent issues with
+	 * decompression algorithms that were spotted during tests;
+	 * even in the case of not using compression, smaller values would
+	 * just pollute more the pstore FS with many small collected files.
+	 */
+	if (record_size < 1024)
+		record_size = 1024;
+
+	efi_pstore_info.buf = kmalloc(record_size, GFP_KERNEL);
 	if (!efi_pstore_info.buf)
 		return -ENOMEM;
 
-	efi_pstore_info.bufsize = 1024;
+	efi_pstore_info.bufsize = record_size;
 
 	if (pstore_register(&efi_pstore_info)) {
 		kfree(efi_pstore_info.buf);