Change in coreboot[master]: cbfstool: Remove location pointer from parse_elf_to_stage()

[Julius Werner (Code Review)]

Attention is currently required from: Furquan Shaikh, Aaron Durbin.
Hello Furquan Shaikh, Aaron Durbin,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/49369

to review the following change.

Change subject: cbfstool: Remove location pointer from parse_elf_to_stage()
......................................................................

cbfstool: Remove location pointer from parse_elf_to_stage()

The *location argument to parse_elf_to_stage() is a relic from code all
the way back to 2009 where this function was still used to parse XIP
stages. Nowadays we have a separate parse_elf_to_xip_stage() for that,
so there is no need to heed XIP concerns here. Having a pointer to
represent the location in flash is absolutely irrelevant to a non-XIP
stage, and it is used incorrectly -- we just get lucky that no code path
in cbfstool can currently lead to that value being anything other than
0, otherwise the adjustment of data_start to be no lower than *location
could easily screw things up. This patch removes it.

Signed-off-by: Julius Werner 
Change-Id: Ia7f850c0edd7536ed3bef643efaae7271599313d
---
M util/cbfstool/cbfs-mkstage.c
M util/cbfstool/cbfstool.c
M util/cbfstool/common.h
3 files changed, 9 insertions(+), 26 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/69/49369/1

diff --git a/util/cbfstool/cbfs-mkstage.c b/util/cbfstool/cbfs-mkstage.c
index bfe7bf8..bd1cf54 100644
--- a/util/cbfstool/cbfs-mkstage.c
+++ b/util/cbfstool/cbfs-mkstage.c
@@ -93,8 +93,7 @@
  * works for all elf files, not just the restricted set.
  */
 int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
-		       enum cbfs_compression algo, uint32_t *location,
-		       const char *ignore_section)
+		       enum cbfs_compression algo, const char *ignore_section)
 {
    struct parsed_elf pelf;
    Elf64_Phdr *phdr;
@@ -113,8 +112,6 @@
    if (!compress)
    	return -1;

-	DEBUG("start: parse_elf_to_stage(location=0x%x)\n", *location);
-
    int flags = ELF_PARSE_PHDR | ELF_PARSE_SHDR | ELF_PARSE_STRTAB;

if (parse_elf(input, &pelf, flags)) {
@@ -174,10 +171,6 @@
    		virt_to_phys = phdr[i].p_paddr - phdr[i].p_vaddr;
    }

-	if (data_start < *location) {
-		data_start = *location;
-	}
-
    if (data_end <= data_start) {
    	ERROR("data ends (%08lx) before it starts (%08lx). Make sure "
    	      "the ELF file is correct and resides in ROM space.\n",
@@ -196,27 +189,19 @@
    /* Copy the file data into the buffer */

for (i = 0; i < headers; i++) {
-		uint64_t l_start, l_offset = 0;
-
    	if (phdr[i].p_type != PT_LOAD)
    		continue;

if (phdr[i].p_memsz == 0)
    		continue;

-		l_start = phdr[i].p_paddr;
-		if (l_start < *location) {
-			l_offset = *location - l_start;
-			l_start = *location;
-		}
-
    	/* A legal ELF file can have a program header with
    	 * non-zero length but zero-length file size and a
    	 * non-zero offset which, added together, are > than
    	 * input->size (i.e. the total file size).  So we need
    	 * to not even test in the case that p_filesz is zero.
    	 */
-		if (! phdr[i].p_filesz)
+		if (!phdr[i].p_filesz)
    		continue;
    	if (input->size < (phdr[i].p_offset + phdr[i].p_filesz)){
    		ERROR("Underflow copying out the segment."
@@ -225,9 +210,9 @@
    		free(buffer);
    		goto err;
    	}
-		memcpy(buffer + (l_start - data_start),
-		       &input->data[phdr[i].p_offset + l_offset],
-		       phdr[i].p_filesz - l_offset);
+		memcpy(buffer + (phdr[i].p_paddr - data_start),
+		       &input->data[phdr[i].p_offset],
+		       phdr[i].p_filesz);
    }

/* Now make the output buffer */
@@ -303,8 +288,6 @@
    fill_cbfs_stage(&outheader, algo, ehdr->e_entry + virt_to_phys,
    		data_start, outlen, mem_end - data_start);

-	if (*location)
-		*location -= sizeof(struct cbfs_stage);
    output->size = sizeof(struct cbfs_stage) + outlen;
    ret = 0;

diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c
index bda1c2f..e1eccc5 100644
--- a/util/cbfstool/cbfstool.c
+++ b/util/cbfstool/cbfstool.c
@@ -1113,9 +1113,10 @@

ret = parse_elf_to_xip_stage(buffer, &output, offset,
    					param.ignore_section);
-	} else
+	} else {
    	ret = parse_elf_to_stage(buffer, &output, param.compression,
-					 offset, param.ignore_section);
+					 param.ignore_section);
+	}

if (ret != 0)
    	return -1;
diff --git a/util/cbfstool/common.h b/util/cbfstool/common.h
index 1c83045..db9c7e7 100644
--- a/util/cbfstool/common.h
+++ b/util/cbfstool/common.h
@@ -174,8 +174,7 @@
    			 enum cbfs_compression algo);
 /* cbfs-mkstage.c */
 int parse_elf_to_stage(const struct buffer *input, struct buffer *output,
-		       enum cbfs_compression algo, uint32_t *location,
-		       const char *ignore_section);
+		       enum cbfs_compression algo, const char *ignore_section);
 /* location is TOP aligned. */
 int parse_elf_to_xip_stage(const struct buffer *input, struct buffer *output,
    			uint32_t *location, const char *ignore_section);