|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 1/4] xen/ppc: Switch to medium PIC code model
Switch Xen to the medium PIC code model on Power. Among other things,
this allows us to be load address agnostic and will open the door to
booting on bare metal PowerNV systems that don't use OpenFirmware.
Also update XEN_VIRT_START to 0xc000000000000000, which is equivalent to
address 0x0 when the MMU is off. This prevents Open Firmware from
loading Xen at an offset from its base load address, so the DECL_SECTION
hack in xen.lds.S is no longer required.
Signed-off-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>
---
Changed in v2:
- Remove stray newline
- Use label instead of .+4 in TOC setup branch
xen/arch/ppc/arch.mk | 2 +-
xen/arch/ppc/include/asm/asm-defns.h | 7 +++++
xen/arch/ppc/include/asm/config.h | 2 +-
xen/arch/ppc/ppc64/head.S | 12 +++++---
xen/arch/ppc/xen.lds.S | 44 ++++++++++------------------
5 files changed, 33 insertions(+), 34 deletions(-)
diff --git a/xen/arch/ppc/arch.mk b/xen/arch/ppc/arch.mk
index 7eec22c283..0183b9ac6a 100644
--- a/xen/arch/ppc/arch.mk
+++ b/xen/arch/ppc/arch.mk
@@ -5,7 +5,7 @@ ppc-march-$(CONFIG_POWER_ISA_2_07B) := power8
ppc-march-$(CONFIG_POWER_ISA_3_00) := power9
CFLAGS += -m64 -mlittle-endian -mcpu=$(ppc-march-y)
-CFLAGS += -mstrict-align -mcmodel=large -mabi=elfv2 -mno-altivec -mno-vsx
+CFLAGS += -mstrict-align -mcmodel=medium -mabi=elfv2 -fPIC -mno-altivec
-mno-vsx -msoft-float
LDFLAGS += -m elf64lppc
diff --git a/xen/arch/ppc/include/asm/asm-defns.h
b/xen/arch/ppc/include/asm/asm-defns.h
index 35b1c89d4e..5821f9024d 100644
--- a/xen/arch/ppc/include/asm/asm-defns.h
+++ b/xen/arch/ppc/include/asm/asm-defns.h
@@ -16,6 +16,13 @@
lis reg, (val) @h; \
ori reg, reg, (val) @l; \
+/*
+ * Load the address of a symbol from the TOC into the specified GPR.
+ */
+#define LOAD_REG_ADDR(reg,name) \
+ addis reg,%r2,name@toc@ha; \
+ addi reg,reg,name@toc@l
+
/*
* Depending on how we were booted, the CPU could be running in either
* Little Endian or Big Endian mode. The following trampoline from Linux
diff --git a/xen/arch/ppc/include/asm/config.h
b/xen/arch/ppc/include/asm/config.h
index cb27d2781e..d060f0dca7 100644
--- a/xen/arch/ppc/include/asm/config.h
+++ b/xen/arch/ppc/include/asm/config.h
@@ -39,7 +39,7 @@
name:
#endif
-#define XEN_VIRT_START _AT(UL, 0x400000)
+#define XEN_VIRT_START _AT(UL, 0xc000000000000000)
#define SMP_CACHE_BYTES (1 << 6)
diff --git a/xen/arch/ppc/ppc64/head.S b/xen/arch/ppc/ppc64/head.S
index 02ff520458..4172f1b8ec 100644
--- a/xen/arch/ppc/ppc64/head.S
+++ b/xen/arch/ppc/ppc64/head.S
@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-or-later */
#include <asm/asm-defns.h>
+#include <asm/asm-offsets.h>
.section .text.header, "ax", %progbits
@@ -11,16 +12,19 @@ ENTRY(start)
FIXUP_ENDIAN
/* set up the TOC pointer */
- LOAD_IMM32(%r2, .TOC.)
+ bcl 20, 31, 1f
+1: mflr %r12
+ addis %r2, %r12, .TOC.-1b@ha
+ addi %r2, %r2, .TOC.-1b@l
/* set up the initial stack */
- LOAD_IMM32(%r1, cpu0_boot_stack)
+ LOAD_REG_ADDR(%r1, cpu0_boot_stack)
li %r11, 0
stdu %r11, -STACK_FRAME_OVERHEAD(%r1)
/* clear .bss */
- LOAD_IMM32(%r14, __bss_start)
- LOAD_IMM32(%r15, __bss_end)
+ LOAD_REG_ADDR(%r14, __bss_start)
+ LOAD_REG_ADDR(%r15, __bss_end)
1:
std %r11, 0(%r14)
addi %r14, %r14, 8
diff --git a/xen/arch/ppc/xen.lds.S b/xen/arch/ppc/xen.lds.S
index c628cc0e5c..2fa81d5a83 100644
--- a/xen/arch/ppc/xen.lds.S
+++ b/xen/arch/ppc/xen.lds.S
@@ -15,25 +15,12 @@ PHDRS
#endif
}
-/**
- * OpenFirmware's base load address is 0x400000 (XEN_VIRT_START).
- * By defining sections this way, we can keep our virtual address base at
0x400000
- * while keeping the physical base at 0x0.
- *
- * Otherwise, OpenFirmware incorrectly loads .text at 0x400000 + 0x400000 =
0x800000.
- * Taken from x86/xen.lds.S
- */
-#ifdef CONFIG_LD_IS_GNU
-# define DECL_SECTION(x) x : AT(ADDR(#x) - XEN_VIRT_START)
-#else
-# define DECL_SECTION(x) x : AT(ADDR(x) - XEN_VIRT_START)
-#endif
-
SECTIONS
{
. = XEN_VIRT_START;
+ _start = .;
- DECL_SECTION(.text) {
+ .text : {
_stext = .; /* Text section */
*(.text.header)
@@ -52,7 +39,7 @@ SECTIONS
} :text
. = ALIGN(PAGE_SIZE);
- DECL_SECTION(.rodata) {
+ .rodata : {
_srodata = .; /* Read-only data */
*(.rodata)
*(.rodata.*)
@@ -67,7 +54,7 @@ SECTIONS
#if defined(BUILD_ID)
. = ALIGN(4);
- DECL_SECTION(.note.gnu.build-id) {
+ .note.gnu.build-id : {
__note_gnu_build_id_start = .;
*(.note.gnu.build-id)
__note_gnu_build_id_end = .;
@@ -76,19 +63,19 @@ SECTIONS
_erodata = .; /* End of read-only data */
. = ALIGN(PAGE_SIZE);
- DECL_SECTION(.data.ro_after_init) {
+ .data.ro_after_init : {
__ro_after_init_start = .;
*(.data.ro_after_init)
. = ALIGN(PAGE_SIZE);
__ro_after_init_end = .;
- } : text
+ } :text
- DECL_SECTION(.data.read_mostly) {
+ .data.read_mostly : {
*(.data.read_mostly)
} :text
. = ALIGN(PAGE_SIZE);
- DECL_SECTION(.data) { /* Data */
+ .data : { /* Data */
*(.data.page_aligned)
. = ALIGN(8);
__start_schedulers_array = .;
@@ -103,7 +90,7 @@ SECTIONS
. = ALIGN(PAGE_SIZE); /* Init code and data */
__init_begin = .;
- DECL_SECTION(.init.text) {
+ .init.text : {
_sinittext = .;
*(.init.text)
_einittext = .;
@@ -111,7 +98,7 @@ SECTIONS
} :text
. = ALIGN(PAGE_SIZE);
- DECL_SECTION(.init.data) {
+ .init.data : {
*(.init.rodata)
*(.init.rodata.*)
@@ -140,18 +127,18 @@ SECTIONS
__ctors_end = .;
} :text
- DECL_SECTION(.got) {
- *(.got)
+ .got : {
+ *(.got .toc)
} :text
- DECL_SECTION(.got.plt) {
+ .got.plt : {
*(.got.plt)
} :text
. = ALIGN(POINTER_ALIGN);
__init_end = .;
- DECL_SECTION(.bss) { /* BSS */
+ .bss : { /* BSS */
__bss_start = .;
*(.bss.stack_aligned)
*(.bss.page_aligned)
@@ -167,10 +154,11 @@ SECTIONS
. = ALIGN(POINTER_ALIGN);
__bss_end = .;
} :text
+
_end = . ;
/* Section for the device tree blob (if any). */
- DECL_SECTION(.dtb) { *(.dtb) } :text
+ .dtb : { *(.dtb) } :text
DWARF2_DEBUG_SECTIONS
--
2.30.2
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |