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Commit 2f127229 authored by Lingutla Chandrasekhar's avatar Lingutla Chandrasekhar Committed by Isaac J. Manjarres
Browse files

elf: Add elf headers helpers support 



ELF header format is been used in multiple places,
add helper functions to get section, program headers, and
string table section details of the elf header.

Change-Id: Ib67b6f25a3a9c32305710eae4ad66bea511d6799
Signed-off-by: default avatarLingutla Chandrasekhar <clingutla@codeaurora.org>
[isaacm@codeaurora.org: Resolve trivial merge conflicts]
Signed-off-by: default avatarIsaac J. Manjarres <isaacm@codeaurora.org>
parent 67f9bdbe

drivers/soc/qcom/msm_minidump.c

+0 −27
Original line number Diff line number Diff line
@@ -87,33 +87,6 @@ bool minidump_enabled; 
static unsigned int pendings;

static unsigned int region_idx = 1; /* First entry is ELF header*/



static inline struct elf_shdr *elf_sheader(struct elfhdr *hdr)

{

	return (struct elf_shdr *)((size_t)hdr + (size_t)hdr->e_shoff);

}



static inline struct elf_shdr *elf_section(struct elfhdr *hdr, int idx)

{

	return &elf_sheader(hdr)[idx];

}



static inline struct elf_phdr *elf_pheader(struct elfhdr *hdr)

{

	return (struct elf_phdr *)((size_t)hdr + (size_t)hdr->e_phoff);

}



static inline struct elf_phdr *elf_program(struct elfhdr *hdr, int idx)

{

	return &elf_pheader(hdr)[idx];

}



static inline char *elf_str_table(struct elfhdr *hdr)

{

	if (hdr->e_shstrndx == SHN_UNDEF)

		return NULL;

	return (char *)hdr + elf_section(hdr, hdr->e_shstrndx)->sh_offset;

}



static inline char *elf_lookup_string(struct elfhdr *hdr, int offset)

{

	char *strtab = elf_str_table(hdr);

drivers/soc/qcom/ramdump.c

+116 −0
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ static DEFINE_MUTEX(rd_minor_mutex); 
static DEFINE_IDA(rd_minor_id);

static bool ramdump_devnode_inited;

#define RAMDUMP_WAIT_MSECS	120000

#define MAX_STRTBL_SIZE 512

#define MAX_NAME_LENGTH 16



struct ramdump_device {

	char name[256];
@@ -447,12 +449,126 @@ static int _do_ramdump(void *handle, struct ramdump_segment *segments, 


}



static inline unsigned int set_section_name(const char *name,

					    struct elfhdr *ehdr)

{

	char *strtab = elf_str_table(ehdr);

	static int strtable_idx = 1;

	int idx, ret = 0;



	idx = strtable_idx;

	if ((strtab == NULL) || (name == NULL))

		return 0;



	ret = idx;

	idx += strlcpy((strtab + idx), name, MAX_NAME_LENGTH);

	strtable_idx = idx + 1;



	return ret;

}



static int _do_minidump(void *handle, struct ramdump_segment *segments,

		int nsegments)

{

	int ret, i;

	struct ramdump_device *rd_dev = (struct ramdump_device *)handle;

	struct elfhdr *ehdr;

	struct elf_shdr *shdr;

	unsigned long offset, strtbl_off;



	if (!rd_dev->consumer_present) {

		pr_err("Ramdump(%s): No consumers. Aborting..\n", rd_dev->name);

		return -EPIPE;

	}



	rd_dev->segments = segments;

	rd_dev->nsegments = nsegments;



	rd_dev->elfcore_size = sizeof(*ehdr) +

			(sizeof(*shdr) * (nsegments + 2)) + MAX_STRTBL_SIZE;

	ehdr = kzalloc(rd_dev->elfcore_size, GFP_KERNEL);

	rd_dev->elfcore_buf = (char *)ehdr;

	if (!rd_dev->elfcore_buf)

		return -ENOMEM;



	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);

	ehdr->e_ident[EI_CLASS] = ELF_CLASS;

	ehdr->e_ident[EI_DATA] = ELF_DATA;

	ehdr->e_ident[EI_VERSION] = EV_CURRENT;

	ehdr->e_ident[EI_OSABI] = ELF_OSABI;

	ehdr->e_type = ET_CORE;

	ehdr->e_machine  = ELF_ARCH;

	ehdr->e_version = EV_CURRENT;

	ehdr->e_ehsize = sizeof(*ehdr);

	ehdr->e_shoff = sizeof(*ehdr);

	ehdr->e_shentsize = sizeof(*shdr);

	ehdr->e_shstrndx = 1;





	offset = rd_dev->elfcore_size;

	shdr = (struct elf_shdr *)(ehdr + 1);

	strtbl_off = sizeof(*ehdr) + sizeof(*shdr) * (nsegments + 2);

	shdr++;

	shdr->sh_type = SHT_STRTAB;

	shdr->sh_offset = (elf_addr_t)strtbl_off;

	shdr->sh_size = MAX_STRTBL_SIZE;

	shdr->sh_entsize = 0;

	shdr->sh_flags = 0;

	shdr->sh_name = set_section_name("STR_TBL", ehdr);

	shdr++;



	for (i = 0; i < nsegments; i++, shdr++) {

		/* Update elf header */

		shdr->sh_type = SHT_PROGBITS;

		shdr->sh_name = set_section_name(segments[i].name, ehdr);

		shdr->sh_addr = (elf_addr_t)segments[i].address;

		shdr->sh_size = segments[i].size;

		shdr->sh_flags = SHF_WRITE;

		shdr->sh_offset = offset;

		shdr->sh_entsize = 0;

		offset += shdr->sh_size;

	}

	ehdr->e_shnum = nsegments + 2;



	rd_dev->data_ready = 1;

	rd_dev->ramdump_status = -1;



	reinit_completion(&rd_dev->ramdump_complete);



	/* Tell userspace that the data is ready */

	wake_up(&rd_dev->dump_wait_q);



	/* Wait (with a timeout) to let the ramdump complete */

	ret = wait_for_completion_timeout(&rd_dev->ramdump_complete,

			msecs_to_jiffies(RAMDUMP_WAIT_MSECS));



	if (!ret) {

		pr_err("Ramdump(%s): Timed out waiting for userspace.\n",

		       rd_dev->name);

		ret = -EPIPE;

	} else {

		ret = (rd_dev->ramdump_status == 0) ? 0 : -EPIPE;

	}



	rd_dev->data_ready = 0;

	rd_dev->elfcore_size = 0;

	kfree(rd_dev->elfcore_buf);

	rd_dev->elfcore_buf = NULL;

	return ret;

}



int do_ramdump(void *handle, struct ramdump_segment *segments, int nsegments)

{

	return _do_ramdump(handle, segments, nsegments, false);

}

EXPORT_SYMBOL(do_ramdump);



int do_minidump(void *handle, struct ramdump_segment *segments, int nsegments)

{

	return _do_minidump(handle, segments, nsegments);

}

EXPORT_SYMBOL(do_minidump);



int

do_elf_ramdump(void *handle, struct ramdump_segment *segments, int nsegments)

{

include/linux/elf.h

+33 −0
Original line number Diff line number Diff line
@@ -45,6 +45,39 @@ extern Elf64_Dyn _DYNAMIC []; 


#endif



/* Generic helpers for ELF use */

/* Return first section header */

static inline struct elf_shdr *elf_sheader(struct elfhdr *hdr)

{

	return (struct elf_shdr *)((size_t)hdr + (size_t)hdr->e_shoff);

}



/* Return idx section header */

static inline struct elf_shdr *elf_section(struct elfhdr *hdr, int idx)

{

	return &elf_sheader(hdr)[idx];

}



/* Return first program header */

static inline struct elf_phdr *elf_pheader(struct elfhdr *hdr)

{

	return (struct elf_phdr *)((size_t)hdr + (size_t)hdr->e_phoff);

}



/* Return idx program header */

static inline struct elf_phdr *elf_program(struct elfhdr *hdr, int idx)

{

	return &elf_pheader(hdr)[idx];

}



/* Retunr section's string table header */

static inline char *elf_str_table(struct elfhdr *hdr)

{

	if (hdr->e_shstrndx == SHN_UNDEF)

		return NULL;

	return (char *)hdr + elf_section(hdr, hdr->e_shstrndx)->sh_offset;

}



/* Optional callbacks to write extra ELF notes. */

struct file;

struct coredump_params;

include/soc/qcom/ramdump.h

+2 −1
Original line number Diff line number Diff line 
/* Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.

/* Copyright (c) 2011-2014, 2017 The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -16,6 +16,7 @@ 
struct device;



struct ramdump_segment {

	char *name;

	unsigned long address;

	void *v_address;

	unsigned long size;