From eb763bec53d6b9aea7a6b60b0cf8c5d8b5f1b35c Mon Sep 17 00:00:00 2001

From: Janosch Frank <frankja@linux.ibm.com>

Date: Thu, 7 Apr 2022 09:48:24 +0000

Subject: [PATCH 14/42] dump: Remove the sh_info variable

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

RH-Author: Cédric Le Goater <clg@redhat.com>

RH-MergeRequest: 226: s390: Enhanced Interpretation for PCI Functions and Secure Execution guest dump

RH-Bugzilla: 1664378 2043909

RH-Acked-by: Thomas Huth <thuth@redhat.com>

RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

RH-Acked-by: Jon Maloy <jmaloy@redhat.com>

RH-Commit: [14/41] 24af12b78c8f5a02cf85df2f6b1d64249f9499c9

There's no need to have phdr_num and sh_info at the same time. We can

make phdr_num 32 bit and set PN_XNUM when we write the header if

phdr_num >= PN_XNUM.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Message-Id: <20220407094824.5074-1-frankja@linux.ibm.com>

(cherry picked from commit 046bc4160bc780eaacc2d702a2589f1a7a01188d)

Signed-off-by: Cédric Le Goater <clg@redhat.com>

---

 dump/dump.c           | 44 +++++++++++++++++++++++--------------------

 include/sysemu/dump.h |  3 +--

 2 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/dump/dump.c b/dump/dump.c

index 9876123f2e..7236b167cc 100644

--- a/dump/dump.c

+++ b/dump/dump.c

@@ -124,6 +124,12 @@ static int fd_write_vmcore(const void *buf, size_t size, void *opaque)

 static void write_elf64_header(DumpState *s, Error **errp)

 {

+    /*

+     * phnum in the elf header is 16 bit, if we have more segments we

+     * set phnum to PN_XNUM and write the real number of segments to a

+     * special section.

+     */

+    uint16_t phnum = MIN(s->phdr_num, PN_XNUM);

     Elf64_Ehdr elf_header;

     int ret;

@@ -138,9 +144,9 @@ static void write_elf64_header(DumpState *s, Error **errp)

     elf_header.e_ehsize = cpu_to_dump16(s, sizeof(elf_header));

     elf_header.e_phoff = cpu_to_dump64(s, sizeof(Elf64_Ehdr));

     elf_header.e_phentsize = cpu_to_dump16(s, sizeof(Elf64_Phdr));

-    elf_header.e_phnum = cpu_to_dump16(s, s->phdr_num);

+    elf_header.e_phnum = cpu_to_dump16(s, phnum);

     if (s->have_section) {

-        uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->sh_info;

+        uint64_t shoff = sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) * s->phdr_num;

         elf_header.e_shoff = cpu_to_dump64(s, shoff);

         elf_header.e_shentsize = cpu_to_dump16(s, sizeof(Elf64_Shdr));

@@ -155,6 +161,12 @@ static void write_elf64_header(DumpState *s, Error **errp)

 static void write_elf32_header(DumpState *s, Error **errp)

 {

+    /*

+     * phnum in the elf header is 16 bit, if we have more segments we

+     * set phnum to PN_XNUM and write the real number of segments to a

+     * special section.

+     */

+    uint16_t phnum = MIN(s->phdr_num, PN_XNUM);

     Elf32_Ehdr elf_header;

     int ret;

@@ -169,9 +181,9 @@ static void write_elf32_header(DumpState *s, Error **errp)

     elf_header.e_ehsize = cpu_to_dump16(s, sizeof(elf_header));

     elf_header.e_phoff = cpu_to_dump32(s, sizeof(Elf32_Ehdr));

     elf_header.e_phentsize = cpu_to_dump16(s, sizeof(Elf32_Phdr));

-    elf_header.e_phnum = cpu_to_dump16(s, s->phdr_num);

+    elf_header.e_phnum = cpu_to_dump16(s, phnum);

     if (s->have_section) {

-        uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->sh_info;

+        uint32_t shoff = sizeof(Elf32_Ehdr) + sizeof(Elf32_Phdr) * s->phdr_num;

         elf_header.e_shoff = cpu_to_dump32(s, shoff);

         elf_header.e_shentsize = cpu_to_dump16(s, sizeof(Elf32_Shdr));

@@ -358,12 +370,12 @@ static void write_elf_section(DumpState *s, int type, Error **errp)

     if (type == 0) {

         shdr_size = sizeof(Elf32_Shdr);

         memset(&shdr32, 0, shdr_size);

-        shdr32.sh_info = cpu_to_dump32(s, s->sh_info);

+        shdr32.sh_info = cpu_to_dump32(s, s->phdr_num);

         shdr = &shdr32;

     } else {

         shdr_size = sizeof(Elf64_Shdr);

         memset(&shdr64, 0, shdr_size);

-        shdr64.sh_info = cpu_to_dump32(s, s->sh_info);

+        shdr64.sh_info = cpu_to_dump32(s, s->phdr_num);

         shdr = &shdr64;

     }

@@ -478,13 +490,6 @@ static void write_elf_loads(DumpState *s, Error **errp)

     hwaddr offset, filesz;

     MemoryMapping *memory_mapping;

     uint32_t phdr_index = 1;

-    uint32_t max_index;

-

-    if (s->have_section) {

-        max_index = s->sh_info;

-    } else {

-        max_index = s->phdr_num;

-    }

     QTAILQ_FOREACH(memory_mapping, &s->list.head, next) {

         get_offset_range(memory_mapping->phys_addr,

@@ -502,7 +507,7 @@ static void write_elf_loads(DumpState *s, Error **errp)

             return;

         }

-        if (phdr_index >= max_index) {

+        if (phdr_index >= s->phdr_num) {

             break;

         }

     }

@@ -1809,22 +1814,21 @@ static void dump_init(DumpState *s, int fd, bool has_format,

         s->phdr_num += s->list.num;

         s->have_section = false;

     } else {

+        /* sh_info of section 0 holds the real number of phdrs */

         s->have_section = true;

-        s->phdr_num = PN_XNUM;

-        s->sh_info = 1; /* PT_NOTE */

         /* the type of shdr->sh_info is uint32_t, so we should avoid overflow */

         if (s->list.num <= UINT32_MAX - 1) {

-            s->sh_info += s->list.num;

+            s->phdr_num += s->list.num;

         } else {

-            s->sh_info = UINT32_MAX;

+            s->phdr_num = UINT32_MAX;

         }

     }

     if (s->dump_info.d_class == ELFCLASS64) {

         if (s->have_section) {

             s->memory_offset = sizeof(Elf64_Ehdr) +

-                               sizeof(Elf64_Phdr) * s->sh_info +

+                               sizeof(Elf64_Phdr) * s->phdr_num +

                                sizeof(Elf64_Shdr) + s->note_size;

         } else {

             s->memory_offset = sizeof(Elf64_Ehdr) +

@@ -1833,7 +1837,7 @@ static void dump_init(DumpState *s, int fd, bool has_format,

     } else {

         if (s->have_section) {

             s->memory_offset = sizeof(Elf32_Ehdr) +

-                               sizeof(Elf32_Phdr) * s->sh_info +

+                               sizeof(Elf32_Phdr) * s->phdr_num +

                                sizeof(Elf32_Shdr) + s->note_size;

         } else {

             s->memory_offset = sizeof(Elf32_Ehdr) +

diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h

index 250143cb5a..b463fc9c02 100644

--- a/include/sysemu/dump.h

+++ b/include/sysemu/dump.h

@@ -154,8 +154,7 @@ typedef struct DumpState {

     GuestPhysBlockList guest_phys_blocks;

     ArchDumpInfo dump_info;

     MemoryMappingList list;

-    uint16_t phdr_num;

-    uint32_t sh_info;

+    uint32_t phdr_num;

     bool have_section;

     bool resume;

     bool detached;

-- 

2.37.3