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From: Philipp Rudo <prudo@linux.vnet.ibm.com>
To: kexec@lists.infradead.org, linux-s390@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Eric Biederman <ebiederm@xmission.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	x86@kernel.org, Dave Young <dyoung@redhat.com>,
	AKASHI Takahiro <takahiro.akashi@linaro.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH v2 08/11] kexec_file: Remove unneeded variables in kexec_purgatory_setup_sechdrs
Date: Wed, 21 Mar 2018 12:27:48 +0100	[thread overview]
Message-ID: <20180321112751.22196-9-prudo@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180321112751.22196-1-prudo@linux.vnet.ibm.com>

The main loop currently uses quite a lot of variables to update the section
headers. Some of them are unnecessary. So clean them up a little.

Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com>
---
 kernel/kexec_file.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 4938f7aacd09..746b91e46e34 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -724,12 +724,8 @@ static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 					 struct kexec_buf *kbuf)
 {
-	unsigned long curr_load_addr;
-	unsigned long load_addr;
 	unsigned long bss_addr;
 	unsigned long offset;
-	unsigned char *buf_addr;
-	unsigned char *src;
 	Elf_Shdr *sechdrs;
 	int i;
 
@@ -762,20 +758,18 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 						sechdrs[i].sh_offset;
 	}
 
-	/* Load SHF_ALLOC sections */
-	buf_addr = kbuf->buffer;
-	load_addr = curr_load_addr = kbuf->mem;
-	bss_addr = load_addr + kbuf->bufsz;
+	offset = 0;
+	bss_addr = kbuf->mem + kbuf->bufsz;
 	kbuf->image->start = pi->ehdr->e_entry;
 
 	for (i = 0; i < pi->ehdr->e_shnum; i++) {
 		unsigned long align;
+		void *src, *dst;
 
 		if (!(sechdrs[i].sh_flags & SHF_ALLOC))
 			continue;
 
 		align = sechdrs[i].sh_addralign;
-
 		if (sechdrs[i].sh_type == SHT_NOBITS) {
 			bss_addr = ALIGN(bss_addr, align);
 			sechdrs[i].sh_addr = bss_addr;
@@ -783,31 +777,27 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
 			continue;
 		}
 
-		curr_load_addr = ALIGN(curr_load_addr, align);
-		offset = curr_load_addr - load_addr;
-		/* We already modifed ->sh_offset to keep src addr */
-		src = (char *)sechdrs[i].sh_offset;
-		memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
-
+		offset = ALIGN(offset, align);
 		if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
 		    pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
 		    pi->ehdr->e_entry < (sechdrs[i].sh_addr
 					 + sechdrs[i].sh_size)) {
 			kbuf->image->start -= sechdrs[i].sh_addr;
-			kbuf->image->start += curr_load_addr;
+			kbuf->image->start += kbuf->mem + offset;
 		}
 
-		/* Store load address and source address of section */
-		sechdrs[i].sh_addr = curr_load_addr;
+		src = (void *)sechdrs[i].sh_offset;
+		dst = pi->purgatory_buf + offset;
+		memcpy(dst, src, sechdrs[i].sh_size);
+
+		sechdrs[i].sh_addr = kbuf->mem + offset;
 
 		/*
 		 * This section got copied to temporary buffer. Update
 		 * ->sh_offset accordingly.
 		 */
-		sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
-
-		/* Advance to the next address */
-		curr_load_addr += sechdrs[i].sh_size;
+		sechdrs[i].sh_offset = (unsigned long)dst;
+		offset += sechdrs[i].sh_size;
 	}
 
 	return 0;
-- 
2.13.5

  parent reply	other threads:[~2018-03-21 11:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-21 11:27 [PATCH v2 00/11] kexec_file: Clean up purgatory load Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 01/11] kexec_file: Silence compile warnings Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 02/11] kexec_file: Remove checks in kexec_purgatory_load Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 03/11] kexec_file: Make purgatory_info->ehdr const Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 04/11] kexec_file: Search symbols in read-only kexec_purgatory Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 05/11] kexec_file: Use read-only sections in arch_kexec_apply_relocations* Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 06/11] kexec_file: Split up __kexec_load_puragory Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 07/11] kexec_file: Remove unneeded for-loop in kexec_purgatory_setup_sechdrs Philipp Rudo
2018-03-21 11:27 ` Philipp Rudo [this message]
2018-03-21 11:27 ` [PATCH v2 09/11] kexec_file: Remove mis-use of sh_offset field during purgatory load Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 10/11] kexec_file: Allow archs to set purgatory load address Philipp Rudo
2018-03-21 11:27 ` [PATCH v2 11/11] kexec_file: Move purgatories sha256 to common code Philipp Rudo
2018-03-21 23:00 ` [PATCH v2 00/11] kexec_file: Clean up purgatory load Andrew Morton
2018-03-23  9:41   ` Philipp Rudo
2018-04-10  6:59     ` Dave Young
2018-03-23  1:03 ` Dave Young

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