arm64: Pass RAM boundary and enable-dcache flag to purgatory

When "enable-dcache" is passed to the kexec() command line, kexec-tools
passes this information to purgatory, which in turn enables cache during
sha-256 verification.

RAM boundary which includes all the sections is needed for creating
identity page mapping and to enable d-cache for those areas. Therefore
these informations are passed to purgatory as well.

Signed-off-by: Pratyush Anand <panand@redhat.com>

kexec/arch/arm64/include/arch/options.h

@@ -7,13 +7,15 @@
 #define OPT_REUSE_CMDLINE	((OPT_MAX)+3)
 #define OPT_PORT		((OPT_MAX)+4)
 #define OPT_PORT_LSR		((OPT_MAX)+5)
-#define OPT_ARCH_MAX		((OPT_MAX)+6)
+#define OPT_ENABLE_DCACHE	((OPT_MAX)+6)
+#define OPT_ARCH_MAX		((OPT_MAX)+7)
 
 #define KEXEC_ARCH_OPTIONS \
 	KEXEC_OPTIONS \
 	{ "append",        1, NULL, OPT_APPEND }, \
 	{ "command-line",  1, NULL, OPT_APPEND }, \
 	{ "dtb",           1, NULL, OPT_DTB }, \
+	{ "enable-dcache", 0, NULL, OPT_ENABLE_DCACHE }, \
 	{ "initrd",        1, NULL, OPT_INITRD }, \
 	{ "ramdisk",       1, NULL, OPT_INITRD }, \
 	{ "reuse-cmdline", 0, NULL, OPT_REUSE_CMDLINE }, \
@@ -28,6 +30,7 @@ static const char arm64_opts_usage[] __attribute__ ((unused)) =
 "     --append=STRING       Set the kernel command line to STRING.\n"
 "     --command-line=STRING Set the kernel command line to STRING.\n"
 "     --dtb=FILE            Use FILE as the device tree blob.\n"
+"     --enable-dcache       Enable D-Cache in Purgatory for faster SHA verification.\n"
 "     --initrd=FILE         Use FILE as the kernel initial ramdisk.\n"
 "     --port=ADDRESS        Purgatory output to port ADDRESS.\n"
 "     --port-lsr=ADDR,VAL   Purgatory output port line status address and TX Empty Bit Field.\n"
@@ -41,6 +44,7 @@ struct arm64_opts {
 	uint64_t port;
 	uint64_t port_lsr;
 	uint8_t port_lsr_val;
+	uint8_t enable_dcache;
 };
 
 extern struct arm64_opts arm64_opts;

kexec/arch/arm64/include/types.h

@@ -0,0 +1,16 @@
+#ifndef _TYPES_H_
+#define _TYPES_H_
+
+#define min(x,y) ({ \
+	typeof(x) _x = (x);	\
+	typeof(y) _y = (y);	\
+	(void) (&_x == &_y);	\
+	_x < _y ? _x : _y; })
+
+#define max(x,y) ({ \
+	typeof(x) _x = (x);	\
+	typeof(y) _y = (y);	\
+	(void) (&_x == &_y);	\
+	_x > _y ? _x : _y; })
+
+#endif /* _TYPES_H_ */

kexec/arch/arm64/kexec-arm64.c

@@ -23,6 +23,7 @@
 #include "fs2dt.h"
 #include "kexec-syscall.h"
 #include "arch/options.h"
+#include "types.h"
 
 /* Global varables the core kexec routines expect. */
 
@@ -136,6 +137,9 @@ int arch_process_options(int argc, char **argv)
 			arm64_opts.port_lsr_val = strtoul(strtok(NULL, ","),
 							NULL, 0);
 			break;
+		case OPT_ENABLE_DCACHE:
+			arm64_opts.enable_dcache = 1;
+			break;
 		default:
 			break; /* Ignore core and unknown options. */
 		}
@@ -454,14 +458,17 @@ static int setup_2nd_dtb(struct dtb *dtb, char *command_line, int on_crash)
 int arm64_load_other_segments(struct kexec_info *info,
 	uint64_t kernel_entry)
 {
-	int result;
+	int result, i;
 	uint64_t dtb_base;
 	uint64_t image_base;
 	unsigned long hole_min;
 	unsigned long hole_max;
+	unsigned long arm64_ram_start = -1;
+	unsigned long arm64_ram_end = 0;
 	uint64_t purgatory_sink;
 	uint64_t purgatory_sink_lsr;
 	uint8_t purgatory_sink_lsr_val;
+	uint8_t purgatory_enable_dcache;
 	char *initrd_buf = NULL;
 	struct dtb dtb;
 	char command_line[COMMAND_LINE_SIZE] = "";
@@ -479,6 +486,7 @@ int arm64_load_other_segments(struct kexec_info *info,
 
 	purgatory_sink_lsr = arm64_opts.port_lsr;
 	purgatory_sink_lsr_val = arm64_opts.port_lsr_val;
+	purgatory_enable_dcache = arm64_opts.enable_dcache;
 
 	if (arm64_opts.dtb) {
 		dtb.name = "dtb_2";
@@ -577,11 +585,25 @@ int arm64_load_other_segments(struct kexec_info *info,
 	elf_rel_set_symbol(&info->rhdr, "arm64_sink_lsr_val",
 		&purgatory_sink_lsr_val, sizeof(purgatory_sink_lsr_val));
 
+	elf_rel_set_symbol(&info->rhdr, "arm64_enable_dcache",
+		&purgatory_enable_dcache, sizeof(purgatory_enable_dcache));
+
 	elf_rel_set_symbol(&info->rhdr, "arm64_kernel_entry", &kernel_entry,
 		sizeof(kernel_entry));
 
 	elf_rel_set_symbol(&info->rhdr, "arm64_dtb_addr", &dtb_base,
 		sizeof(dtb_base));
+	for (i = 0; i < info->nr_segments; i++) {
+		arm64_ram_start = min(arm64_ram_start,
+				(unsigned long)info->segment[i].mem);
+		arm64_ram_end = max(arm64_ram_end,
+				((unsigned long)info->segment[i].mem +
+				 info->segment[i].memsz));
+	}
+	elf_rel_set_symbol(&info->rhdr, "arm64_ram_start",
+			&arm64_ram_start, sizeof(arm64_ram_start));
+	elf_rel_set_symbol(&info->rhdr, "arm64_ram_end",
+			&arm64_ram_end, sizeof(arm64_ram_end));
 
 	return 0;
 }

purgatory/arch/arm64/purgatory-arm64.c

@@ -4,12 +4,16 @@
 
 #include <stdint.h>
 #include <purgatory.h>
+#include "cache.h"
 
 /* Symbols set by kexec. */
 
 uint8_t *arm64_sink __attribute__ ((section ("data")));
 uint8_t *arm64_sink_lsr __attribute__ ((section ("data")));
 uint8_t arm64_sink_lsr_val __attribute__ ((section ("data")));
+uint8_t arm64_enable_dcache __attribute__ ((section ("data")));
+uint64_t arm64_ram_start __attribute__ ((section ("data")));
+uint64_t arm64_ram_end __attribute__ ((section ("data")));
 extern void (*arm64_kernel_entry)(uint64_t, uint64_t, uint64_t, uint64_t);
 extern uint64_t arm64_dtb_addr;
 
@@ -45,10 +49,15 @@ void putchar(int ch)
 
 void post_verification_setup_arch(void)
 {
+	if (arm64_enable_dcache)
+		disable_dcache(arm64_ram_start, arm64_ram_end);
 }
 
 void setup_arch(void)
 {
 	printf("purgatory: entry=%lx\n", (unsigned long)arm64_kernel_entry);
 	printf("purgatory: dtb=%lx\n", arm64_dtb_addr);
+
+	if (arm64_enable_dcache)
+		enable_dcache(arm64_ram_start, arm64_ram_end, (uint64_t)arm64_sink);
 }