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, 154 insertions, 0 deletions

diff --git a/drivers/firmware/efi/libstub/printk.c b/drivers/firmware/efi/libstub/printk.c
new file mode 100644
index 000000000000..3a67a2cea7bd
--- /dev/null
+++ b/drivers/firmware/efi/libstub/printk.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/stdarg.h>
+
+#include <linux/ctype.h>
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
+#include <asm/efi.h>
+#include <asm/setup.h>
+
+#include "efistub.h"
+
+int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+
+/**
+ * efi_char16_puts() - Write a UCS-2 encoded string to the console
+ * @str:	UCS-2 encoded string
+ */
+void efi_char16_puts(efi_char16_t *str)
+{
+	efi_call_proto(efi_table_attr(efi_system_table, con_out),
+		       output_string, str);
+}
+
+static
+u32 utf8_to_utf32(const u8 **s8)
+{
+	u32 c32;
+	u8 c0, cx;
+	size_t clen, i;
+
+	c0 = cx = *(*s8)++;
+	/*
+	 * The position of the most-significant 0 bit gives us the length of
+	 * a multi-octet encoding.
+	 */
+	for (clen = 0; cx & 0x80; ++clen)
+		cx <<= 1;
+	/*
+	 * If the 0 bit is in position 8, this is a valid single-octet
+	 * encoding. If the 0 bit is in position 7 or positions 1-3, the
+	 * encoding is invalid.
+	 * In either case, we just return the first octet.
+	 */
+	if (clen < 2 || clen > 4)
+		return c0;
+	/* Get the bits from the first octet. */
+	c32 = cx >> clen--;
+	for (i = 0; i < clen; ++i) {
+		/* Trailing octets must have 10 in most significant bits. */
+		cx = (*s8)[i] ^ 0x80;
+		if (cx & 0xc0)
+			return c0;
+		c32 = (c32 << 6) | cx;
+	}
+	/*
+	 * Check for validity:
+	 * - The character must be in the Unicode range.
+	 * - It must not be a surrogate.
+	 * - It must be encoded using the correct number of octets.
+	 */
+	if (c32 > 0x10ffff ||
+	    (c32 & 0xf800) == 0xd800 ||
+	    clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
+		return c0;
+	*s8 += clen;
+	return c32;
+}
+
+/**
+ * efi_puts() - Write a UTF-8 encoded string to the console
+ * @str:	UTF-8 encoded string
+ */
+void efi_puts(const char *str)
+{
+	efi_char16_t buf[128];
+	size_t pos = 0, lim = ARRAY_SIZE(buf);
+	const u8 *s8 = (const u8 *)str;
+	u32 c32;
+
+	while (*s8) {
+		if (*s8 == '\n')
+			buf[pos++] = L'\r';
+		c32 = utf8_to_utf32(&s8);
+		if (c32 < 0x10000) {
+			/* Characters in plane 0 use a single word. */
+			buf[pos++] = c32;
+		} else {
+			/*
+			 * Characters in other planes encode into a surrogate
+			 * pair.
+			 */
+			buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
+			buf[pos++] = 0xdc00 + (c32 & 0x3ff);
+		}
+		if (*s8 == '\0' || pos >= lim - 2) {
+			buf[pos] = L'\0';
+			efi_char16_puts(buf);
+			pos = 0;
+		}
+	}
+}
+
+/**
+ * efi_printk() - Print a kernel message
+ * @fmt:	format string
+ *
+ * The first letter of the format string is used to determine the logging level
+ * of the message. If the level is less then the current EFI logging level, the
+ * message is suppressed. The message will be truncated to 255 bytes.
+ *
+ * Return:	number of printed characters
+ */
+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);
+	va_end(args);
+
+	efi_puts(printf_buf);
+	if (printed >= sizeof(printf_buf)) {
+		efi_puts("[Message truncated]\n");
+		return -1;
+	}
+
+	return printed;
+}