[PATCH v7 02/11] arm64/sframe: Read vmlinux .sframe header

@@ -28519,6 +28519,7 @@ M:	Josh Poimboeuf <jpoimboe@kernel.org>
 M:	Steven Rostedt <rostedt@goodmis.org>
 S:	Maintained
 F:	arch/*/include/asm/unwind_sframe.h
+F:	include/linux/sframe.h
 F:	include/linux/unwind*.h
 F:	kernel/unwind/
 

@@ -32,6 +32,7 @@
 #include <linux/sched/task.h>
 #include <linux/scs.h>
 #include <linux/mm.h>
+#include <linux/sframe.h>
 
 #include <asm/acpi.h>
 #include <asm/fixmap.h>

@@ -373,6 +374,7 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 			"This indicates a broken bootloader or old kernel\n",
 			boot_args[1], boot_args[2], boot_args[3]);
 	}
+	init_sframe_table();
 }
 
 static inline bool cpu_can_disable(unsigned int cpu)

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SFRAME_H
+#define _LINUX_SFRAME_H
+
+#include <linux/init.h>
+
+#ifdef CONFIG_UNWIND_SFRAME_LOOKUP
+
+struct sframe_section {
+	unsigned long	sframe_start;
+	unsigned long	sframe_end;
+
+	unsigned long	fdes_start;
+	unsigned long	fres_start;
+	unsigned long	fres_end;
+	unsigned int	num_fdes;
+
+	signed char	ra_off;
+	signed char	fp_off;
+};
+
+extern struct sframe_section kernel_sfsec __ro_after_init;
+
+void __init init_sframe_table(void);
+
+#else /* !CONFIG_UNWIND_SFRAME_LOOKUP */
+
+static inline void __init init_sframe_table(void) {}
+
+#endif /* CONFIG_UNWIND_SFRAME_LOOKUP */
+
+#endif /* _LINUX_SFRAME_H */

@@ -1 +1,2 @@
- obj-$(CONFIG_UNWIND_USER)	+= user.o deferred.o
+ obj-$(CONFIG_UNWIND_USER)		+= user.o deferred.o
+ obj-$(CONFIG_UNWIND_SFRAME_LOOKUP)	+= sframe.o

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel sframe access functions
+ */
+
+#define pr_fmt(fmt)	"sframe: " fmt
+
+#include <linux/mm.h>
+#include <linux/string_helpers.h>
+#include <linux/sframe.h>
+#include <asm/sections.h>
+
+#include "sframe.h"
+
+static bool sframe_init __ro_after_init;
+struct sframe_section kernel_sfsec __ro_after_init;
+
+static int sframe_read_header(struct sframe_section *sec)
+{
+	unsigned long header_end, fdes_start, fdes_end, fres_start, fres_end;
+	struct sframe_header *shdr;
+	unsigned int num_fdes;
+
+	header_end = sec->sframe_start + sizeof(struct sframe_header);
+	if (header_end >= sec->sframe_end) {
+		pr_debug("header struct doesn't fit in section\n");
+		return -EINVAL;
+	}
+
+	shdr = (struct sframe_header *)sec->sframe_start;
+
+	if (shdr->preamble.magic != SFRAME_MAGIC ||
+	    shdr->preamble.version != SFRAME_VERSION_3 ||
+	    !(shdr->preamble.flags & SFRAME_F_FDE_SORTED) ||
+	    !(shdr->preamble.flags & SFRAME_F_FDE_FUNC_START_PCREL) ||
+	    shdr->auxhdr_len) {
+		pr_debug("bad/unsupported sframe header\n");
+		return -EINVAL;
+	}
+
+	if (!shdr->num_fdes || !shdr->num_fres) {
+		pr_debug("no fde/fre entries\n");
+		return -EINVAL;
+	}
+
+	num_fdes   = shdr->num_fdes;
+	fdes_start = header_end + shdr->fdes_off;
+	fdes_end   = fdes_start + (num_fdes * sizeof(struct sframe_fde_v3));
+
+	fres_start = header_end + shdr->fres_off;
+	fres_end   = fres_start + shdr->fre_len;
+
+	if (fres_start < fdes_end || fres_end > sec->sframe_end) {
+		pr_debug("inconsistent fde/fre offsets\n");
+		return -EINVAL;
+	}
+
+	sec->num_fdes		= num_fdes;
+	sec->fdes_start		= fdes_start;
+	sec->fres_start		= fres_start;
+	sec->fres_end		= fres_end;
+
+	sec->ra_off		= shdr->cfa_fixed_ra_offset;
+	sec->fp_off		= shdr->cfa_fixed_fp_offset;
+
+	return 0;
+}
+
+void __init init_sframe_table(void)
+{
+	kernel_sfsec.sframe_start	= (unsigned long)__start_sframe;
+	kernel_sfsec.sframe_end		= (unsigned long)__end_sframe;
+
+	if (sframe_read_header(&kernel_sfsec)) {
+		pr_warn("invalid vmlinux SFrame header\n");
+		return;
+	}
+
+	sframe_init = true;
+}

@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * From https://www.sourceware.org/binutils/docs/sframe-spec.html
+ */
+#ifndef _SFRAME_H
+#define _SFRAME_H
+
+#include <linux/types.h>
+
+#define SFRAME_VERSION_1			1
+#define SFRAME_VERSION_2			2
+#define SFRAME_VERSION_3			3
+#define SFRAME_MAGIC				0xdee2
+
+#define SFRAME_F_FDE_SORTED			0x1
+#define SFRAME_F_FRAME_POINTER			0x2
+#define SFRAME_F_FDE_FUNC_START_PCREL		0x4
+
+#define SFRAME_ABI_AARCH64_ENDIAN_BIG		1
+#define SFRAME_ABI_AARCH64_ENDIAN_LITTLE	2
+#define SFRAME_ABI_AMD64_ENDIAN_LITTLE		3
+
+struct sframe_preamble {
+	u16	magic;
+	u8	version;
+	u8	flags;
+} __packed;
+
+struct sframe_header {
+	struct sframe_preamble preamble;
+	u8	abi_arch;
+	s8	cfa_fixed_fp_offset;
+	s8	cfa_fixed_ra_offset;
+	u8	auxhdr_len;
+	u32	num_fdes;
+	u32	num_fres;
+	u32	fre_len;
+	u32	fdes_off;
+	u32	fres_off;
+} __packed;
+
+struct sframe_fde_v3 {
+	s64	func_start_off;
+	u32	func_size;
+	u32	fres_off;
+} __packed;
+
+struct sframe_fda_v3 {
+	u16	fres_num;
+	u8	info;
+	u8	info2;
+	u8	rep_size;
+} __packed;
+
+#define SFRAME_FDE_PCTYPE_INC			0
+#define SFRAME_FDE_PCTYPE_MASK			1
+
+#define SFRAME_AARCH64_PAUTH_KEY_A		0
+#define SFRAME_AARCH64_PAUTH_KEY_B		1
+
+#define SFRAME_V3_FDE_FRE_TYPE(info)		((info) & 0xf)
+#define SFRAME_V3_FDE_PCTYPE(info)		(((info) >> 4) & 0x1)
+#define SFRAME_V3_AARCH64_FDE_PAUTH_KEY(info)	(((info) >> 5) & 0x1)
+
+#define SFRAME_FDE_TYPE_DEFAULT			0
+
+#define SFRAME_V3_FDE_TYPE_MASK			0x1f
+#define SFRAME_V3_FDE_TYPE(info2)		((info2) & SFRAME_V3_FDE_TYPE_MASK)
+
+#define SFRAME_BASE_REG_FP			0
+#define SFRAME_BASE_REG_SP			1
+
+#define SFRAME_V3_FRE_CFA_BASE_REG_ID(info)		((info) & 0x1)
+#define SFRAME_V3_FRE_DATAWORD_COUNT(info)		(((info) >> 1) & 0xf)
+#define SFRAME_V3_FRE_DATAWORD_SIZE(info)		(((info) >> 5) & 0x3)
+#define SFRAME_V3_AARCH64_FRE_MANGLED_RA_P(info)	(((info) >> 7) & 0x1)
+
+#endif /* _SFRAME_H */