From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Fri, 22 Oct 2021 09:53:15 +1100
Subject: [PATCH] powerpc-ieee1275: load grub at 4MB, not 2MB
This was first reported under PFW but reproduces under SLOF.
- The core.elf was 2126152 = 0x207148 bytes in size with the following
program headers (per readelf):
Entry point 0x200000
There are 4 program headers, starting at offset 52
Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x000160 0x00200000 0x00200000 0x21f98 0x2971c RWE 0x8
GNU_STACK 0x0220f8 0x00000000 0x00000000 0x00000 0x00000 RWE 0x4
LOAD 0x0220f8 0x00232000 0x00232000 0x1e4e50 0x1e4e50 RWE 0x4
NOTE 0x206f48 0x00000000 0x00000000 0x00200 0x00000 R 0x4
- SLOF places the ELF file at 0x4000 (after the reserved space for
interrupt handlers etc.) upwards. The image was 2126152 = 0x207148
bytes in size, so it runs from 0x4000 - 0x20b148. We'll call 0x4000 the
load address.
0x0 0x4000 0x20b148
|----------|--------------|
| reserved | ELF contents |
- SLOF then copies the first LOAD program header (for .text). That runs
for 0x21f98 bytes. It runs from
(load addr + 0x160) to (load addr + 0x160 + 0x21f98)
= 0x4160 to 0x260f8
and we copy it to 0x200000 to 0x221f98. This overwrites the end of the
image:
0x0 0x4000 0x200000 0x221f98
|----------|------------|---------------|
| reserved | ELF cont.. | .text section |
- SLOF zeros the bss up to PhysAddr + MemSize = 0x22971c
0x0 0x4000 0x200000 0x221f98 0x22971c
|----------|------------|---------------|--------|
| reserved | ELF cont.. | .text section | bss 0s |
- SLOF then goes to fulfil the next LOAD header (for mods), which is
for 0x1e4e50 bytes. We copy from
(load addr + 0x220f8) to (load addr + 0x220f8 + 0x1e4e50)
= 0x260f8 to 0x20af48
and we copy it to 0x232000 to 0x416e50:
0x0 0x4000 0x200000 0x221f98 0x22971c
|----------|------------|---------------|--------|
| reserved | ELF cont.. | .text section | bss 0s |
|-------------|
| copied area |
0x260f8 0x20af48
This goes poorly:
0x0 0x4000 0x200000 0x221f98 0x22971c 0x232000 0x40bf08 0x416e50
|----------|------------|---------------|--------|-----|-----------|-------------|
| reserved | ELF cont.. | .text section | bss 0s | pad | some mods | .text start |
This matches the observations on the running system - 0x40bf08 was where
the contents of memory no longer matched the contents of the ELF file.
This was reported as a license verification failure on SLOF as the
last module's .module_license section fell past where the corruption
began.
Signed-off-by: Daniel Axtens <dja@axtens.net>
[rharwood@redhat.com: trim very detailed commit message]
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
grub-core/Makefile.core.def | 2 +-
include/grub/offsets.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 4a57de975e..08ac0fb15f 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -89,7 +89,7 @@ kernel = {
i386_xen_pvh_ldflags = '$(TARGET_IMG_BASE_LDOPT),0x100000';
mips_loongson_ldflags = '-Wl,-Ttext,0x80200000';
- powerpc_ieee1275_ldflags = '-Wl,-Ttext,0x200000';
+ powerpc_ieee1275_ldflags = '-Wl,-Ttext,0x400000';
sparc64_ieee1275_ldflags = '-Wl,-Ttext,0x4400';
mips_arc_ldflags = '-Wl,-Ttext,$(TARGET_LINK_ADDR)';
mips_qemu_mips_ldflags = '-Wl,-Ttext,0x80200000';
diff --git a/include/grub/offsets.h b/include/grub/offsets.h
index 871e1cd4c3..69211aa798 100644
--- a/include/grub/offsets.h
+++ b/include/grub/offsets.h
@@ -63,7 +63,7 @@
#define GRUB_KERNEL_SPARC64_IEEE1275_LINK_ADDR 0x4400
#define GRUB_KERNEL_POWERPC_IEEE1275_LINK_ALIGN 4
-#define GRUB_KERNEL_POWERPC_IEEE1275_LINK_ADDR 0x200000
+#define GRUB_KERNEL_POWERPC_IEEE1275_LINK_ADDR 0x400000
#define GRUB_KERNEL_MIPS_LOONGSON_LINK_ADDR 0x80200000