Merge tag 'x86-boot-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
 "Misc updates:

   - Add the initrdmem= boot option to specify an initrd embedded in RAM
     (flash most likely)

   - Sanitize the CS value earlier during boot, which also fixes SEV-ES

   - Various fixes and smaller cleanups"

* tag 'x86-boot-2020-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Correct relocation destination on old linkers
  x86/boot/compressed/64: Switch to __KERNEL_CS after GDT is loaded
  x86/boot: Fix -Wint-to-pointer-cast build warning
  x86/boot: Add kstrtoul() from lib/
  x86/tboot: Mark tboot static
  x86/setup: Add an initrdmem= option to specify initrd physical address

7 files changed, 70 insertions, 9 deletions

diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index ef2ad7253cd5..8bcbcee54aa1 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -280,9 +280,9 @@ acpi_physical_address get_rsdp_addr(void)
  */
 #define MAX_ADDR_LEN 19
 
-static acpi_physical_address get_cmdline_acpi_rsdp(void)
+static unsigned long get_cmdline_acpi_rsdp(void)
 {
-	acpi_physical_address addr = 0;
+	unsigned long addr = 0;
 
 #ifdef CONFIG_KEXEC
 	char val[MAX_ADDR_LEN] = { };
@@ -292,7 +292,7 @@ static acpi_physical_address get_cmdline_acpi_rsdp(void)
 	if (ret < 0)
 		return 0;
 
-	if (kstrtoull(val, 16, &addr))
+	if (boot_kstrtoul(val, 16, &addr))
 		return 0;
 #endif
 	return addr;
@@ -314,7 +314,6 @@ static unsigned long get_acpi_srat_table(void)
 	 * different ideas about whether to trust a command-line parameter.
 	 */
 	rsdp = (struct acpi_table_rsdp *)get_cmdline_acpi_rsdp();
-
 	if (!rsdp)
 		rsdp = (struct acpi_table_rsdp *)(long)
 			boot_params->acpi_rsdp_addr;
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index ab3307036ba4..03557f2174bf 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -49,16 +49,17 @@
  * Position Independent Executable (PIE) so that linker won't optimize
  * R_386_GOT32X relocation to its fixed symbol address.  Older
  * linkers generate R_386_32 relocations against locally defined symbols,
- * _bss, _ebss, _got and _egot, in PIE.  It isn't wrong, just less
+ * _bss, _ebss, _got, _egot and _end, in PIE.  It isn't wrong, just less
  * optimal than R_386_RELATIVE.  But the x86 kernel fails to properly handle
  * R_386_32 relocations when relocating the kernel.  To generate
- * R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as
+ * R_386_RELATIVE relocations, we mark _bss, _ebss, _got, _egot and _end as
  * hidden:
  */
 	.hidden _bss
 	.hidden _ebss
 	.hidden _got
 	.hidden _egot
+	.hidden _end
 
 	__HEAD
 SYM_FUNC_START(startup_32)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 4f7e6b84be07..e821a7d7d5c4 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -42,6 +42,7 @@
 	.hidden _ebss
 	.hidden _got
 	.hidden _egot
+	.hidden _end
 
 	__HEAD
 	.code32
@@ -393,6 +394,14 @@ SYM_CODE_START(startup_64)
 	addq	%rax, 2(%rax)
 	lgdt	(%rax)
 
+	/* Reload CS so IRET returns to a CS actually in the GDT */
+	pushq	$__KERNEL_CS
+	leaq	.Lon_kernel_cs(%rip), %rax
+	pushq	%rax
+	lretq
+
+.Lon_kernel_cs:
+
 	/*
 	 * paging_prepare() sets up the trampoline and checks if we need to
 	 * enable 5-level paging.
diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 8272a4492844..8a3fff9128bb 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -117,7 +117,6 @@ static unsigned int simple_guess_base(const char *cp)
  * @endp: A pointer to the end of the parsed string will be placed here
  * @base: The number base to use
  */
-
 unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
 {
 	unsigned long long result = 0;
@@ -335,3 +334,45 @@ int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
 		s++;
 	return _kstrtoull(s, base, res);
 }
+
+static int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+	unsigned long long tmp;
+	int rv;
+
+	rv = kstrtoull(s, base, &tmp);
+	if (rv < 0)
+		return rv;
+	if (tmp != (unsigned long)tmp)
+		return -ERANGE;
+	*res = tmp;
+	return 0;
+}
+
+/**
+ * kstrtoul - convert a string to an unsigned long
+ * @s: The start of the string. The string must be null-terminated, and may also
+ *  include a single newline before its terminating null. The first character
+ *  may also be a plus sign, but not a minus sign.
+ * @base: The number base to use. The maximum supported base is 16. If base is
+ *  given as 0, then the base of the string is automatically detected with the
+ *  conventional semantics - If it begins with 0x the number will be parsed as a
+ *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
+ *  parsed as an octal number. Otherwise it will be parsed as a decimal.
+ * @res: Where to write the result of the conversion on success.
+ *
+ * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
+ * Used as a replacement for the simple_strtoull.
+ */
+int boot_kstrtoul(const char *s, unsigned int base, unsigned long *res)
+{
+	/*
+	 * We want to shortcut function call, but
+	 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
+	 */
+	if (sizeof(unsigned long) == sizeof(unsigned long long) &&
+	    __alignof__(unsigned long) == __alignof__(unsigned long long))
+		return kstrtoull(s, base, (unsigned long long *)res);
+	else
+		return _kstrtoul(s, base, res);
+}
diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h
index 38d8f2f5e47e..995f7b7ad512 100644
--- a/arch/x86/boot/string.h
+++ b/arch/x86/boot/string.h
@@ -30,4 +30,5 @@ extern unsigned long long simple_strtoull(const char *cp, char **endp,
 					  unsigned int base);
 
 int kstrtoull(const char *s, unsigned int base, unsigned long long *res);
+int boot_kstrtoul(const char *s, unsigned int base, unsigned long *res);
 #endif /* BOOT_STRING_H */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4b3fa6cd3106..a3767e74c758 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -237,6 +237,9 @@ static u64 __init get_ramdisk_image(void)
 
 	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
 
+	if (ramdisk_image == 0)
+		ramdisk_image = phys_initrd_start;
+
 	return ramdisk_image;
 }
 static u64 __init get_ramdisk_size(void)
@@ -245,6 +248,9 @@ static u64 __init get_ramdisk_size(void)
 
 	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
 
+	if (ramdisk_size == 0)
+		ramdisk_size = phys_initrd_size;
+
 	return ramdisk_size;
 }
 
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index b89f6ac6a0c0..b2942b2dbfcf 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -35,8 +35,7 @@
 #include "../realmode/rm/wakeup.h"
 
 /* Global pointer to shared data; NULL means no measured launch. */
-struct tboot *tboot __read_mostly;
-EXPORT_SYMBOL(tboot);
+static struct tboot *tboot __read_mostly;
 
 /* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
 #define AP_WAIT_TIMEOUT		1
@@ -46,6 +45,11 @@ EXPORT_SYMBOL(tboot);
 
 static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
 
+bool tboot_enabled(void)
+{
+	return tboot != NULL;
+}
+
 void __init tboot_probe(void)
 {
 	/* Look for valid page-aligned address for shared page. */