[Fedora kexec-tools 7/7] kexec: Pass acpi_rsdp info in bootparams

[Vivek Goyal]

Secureboot and securemodules don't trust a pointer to executable code as
passed on command line as it is modifiable by root. So pass this info in
bootparams.

Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
---
 include/x86/x86-linux.h           |  3 ++-
 kexec/arch/i386/x86-linux-setup.c | 26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/x86/x86-linux.h b/include/x86/x86-linux.h
index bf4f8bb..416bb1b 100644
--- a/include/x86/x86-linux.h
+++ b/include/x86/x86-linux.h
@@ -115,7 +115,8 @@ struct x86_linux_param_header {
 	uint32_t ext_ramdisk_image;		/* 0xc0 */
 	uint32_t ext_ramdisk_size;		/* 0xc4 */
 	uint32_t ext_cmd_line_ptr;		/* 0xc8 */
-	uint8_t reserved4_1[0x1e0 - 0xcc];	/* 0xcc */
+	uint64_t acpi_rsdp_addr;		/* 0xcc */
+	uint8_t reserved4_1[0x1e0 - 0xd4];	/* 0xd4 */
 	uint32_t alt_mem_k;			/* 0x1e0 */
 	uint8_t  reserved5[4];			/* 0x1e4 */
 	uint8_t  e820_map_nr;			/* 0x1e8 */
diff --git a/kexec/arch/i386/x86-linux-setup.c b/kexec/arch/i386/x86-linux-setup.c
index e244821..6dec787 100644
--- a/kexec/arch/i386/x86-linux-setup.c
+++ b/kexec/arch/i386/x86-linux-setup.c
@@ -47,6 +47,31 @@ void init_linux_parameters(struct x86_linux_param_header *real_mode)
 	real_mode->cmdline_size = COMMAND_LINE_SIZE;
 }
 
+static void setup_acpi_rsdp_bootparam(struct x86_linux_param_header *real_mode)
+{
+	FILE *fp;
+	char line[MAX_LINE], *s;
+	unsigned long long acpi_rsdp_addr = 0;
+
+	fp = fopen("/sys/firmware/efi/systab", "r");
+	if (!fp)
+		return;
+
+	while(fgets(line, sizeof(line), fp) != 0) {
+		/* ACPI20= always goes before ACPI= */
+		if ((strstr(line, "ACPI20=")) || (strstr(line, "ACPI="))) {
+			line[strlen(line) - 1] = '\0';
+			s = strchr(line, '=');
+			s += 1;
+			acpi_rsdp_addr = strtoull(s, NULL, 16);
+			break;
+		}
+	}
+
+	fclose(fp);
+	real_mode->acpi_rsdp_addr = acpi_rsdp_addr;
+}
+
 void setup_linux_bootloader_parameters_high(
 	struct kexec_info *info, struct x86_linux_param_header *real_mode,
 	unsigned long real_mode_base, unsigned long cmdline_offset,
@@ -121,6 +146,7 @@ void setup_linux_bootloader_parameters_high(
 	memcpy(cmdline_ptr, cmdline, cmdline_len);
 	cmdline_ptr[cmdline_len - 1] = '\0';
 	real_mode->secure_boot = is_secureboot_enabled();
+	setup_acpi_rsdp_bootparam(real_mode);
 }
 
 int setup_linux_vesafb(struct x86_linux_param_header *real_mode)
-- 
1.8.3.1