From: "tip-bot for H. Peter Anvin" <hpa@linux.intel.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org,
tglx@linutronix.de, hpa@linux.intel.com
Subject: [tip:x86/trampoline] x86, realmode: Replace open-coded ljmpw with a macro
Date: Tue, 8 May 2012 15:24:58 -0700 [thread overview]
Message-ID: <tip-e5684ec438a094bec0f7d5c52652c0901b48b613@git.kernel.org> (raw)
In-Reply-To: <1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com>
Commit-ID: e5684ec438a094bec0f7d5c52652c0901b48b613
Gitweb: http://git.kernel.org/tip/e5684ec438a094bec0f7d5c52652c0901b48b613
Author: H. Peter Anvin <hpa@linux.intel.com>
AuthorDate: Tue, 8 May 2012 21:22:37 +0300
Committer: H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 8 May 2012 11:48:03 -0700
x86, realmode: Replace open-coded ljmpw with a macro
We cannot code an ljmpw to the real-mode segment directly, because gas
refuses to assemble an ljmp with a symbolic segment. Instead of
open-coding it everywhere, define a macro and use it for this case.
This is specifically an ljmpw from a 16-bit segment. This is okay, as
one should never enter real mode from a 32-bit segment: if one do, the
CPU ends up in a bizarre (and useless) mode sometimes called "unreal
mode" where segments behave like real mode but the default address and
operand sizes is 32 bits.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com
---
arch/x86/realmode/rm/realmode.h | 16 ++++++++++++++++
arch/x86/realmode/rm/reboot_32.S | 6 ++----
arch/x86/realmode/rm/trampoline_32.S | 5 ++---
arch/x86/realmode/rm/trampoline_64.S | 5 ++---
arch/x86/realmode/rm/wakeup/wakeup_asm.S | 9 +++------
5 files changed, 25 insertions(+), 16 deletions(-)
diff --git a/arch/x86/realmode/rm/realmode.h b/arch/x86/realmode/rm/realmode.h
new file mode 100644
index 0000000..15ab633
--- /dev/null
+++ b/arch/x86/realmode/rm/realmode.h
@@ -0,0 +1,16 @@
+#ifndef ARCH_X86_REALMODE_RM_REALMODE_H
+#define ARCH_X86_REALMODE_RM_REALMODE_H
+
+#ifdef __ASSEMBLY__
+
+/*
+ * 16-bit ljmpw to the real_mode_seg
+ *
+ * This must be open-coded since gas will choke on using a
+ * relocatable symbol for the segment portion.
+ */
+#define LJMPW_RM(to) .byte 0xea ; .word (to), real_mode_seg
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* ARCH_X86_REALMODE_RM_REALMODE_H */
diff --git a/arch/x86/realmode/rm/reboot_32.S b/arch/x86/realmode/rm/reboot_32.S
index 83803c2..e90f8c4 100644
--- a/arch/x86/realmode/rm/reboot_32.S
+++ b/arch/x86/realmode/rm/reboot_32.S
@@ -2,6 +2,7 @@
#include <linux/init.h>
#include <asm/segment.h>
#include <asm/page_types.h>
+#include "realmode.h"
/*
* The following code and data reboots the machine by switching to real
@@ -82,10 +83,7 @@ machine_real_restart_asm16:
2:
andb $0x10, %dl
movl %edx, %cr0
- .byte 0xea /* ljmpw */
- .word 3f /* Offset */
- .word real_mode_seg /* Segment */
-
+ LJMPW_RM(3f)
3:
testb $0, %al
jz bios
diff --git a/arch/x86/realmode/rm/trampoline_32.S b/arch/x86/realmode/rm/trampoline_32.S
index 1315ef4..279f82e 100644
--- a/arch/x86/realmode/rm/trampoline_32.S
+++ b/arch/x86/realmode/rm/trampoline_32.S
@@ -29,6 +29,7 @@
#include <linux/init.h>
#include <asm/segment.h>
#include <asm/page_types.h>
+#include "realmode.h"
.text
.code16
@@ -38,9 +39,7 @@
trampoline_data:
wbinvd # Needed for NUMA-Q should be harmless for others
- .byte 0xea # ljmpw
- .word 1f # Offset
- .word real_mode_seg # Segment
+ LJMPW_RM(1f)
1:
mov %cs, %ax # Code and data in the same place
mov %ax, %ds
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S
index 77b72b4..7459c52 100644
--- a/arch/x86/realmode/rm/trampoline_64.S
+++ b/arch/x86/realmode/rm/trampoline_64.S
@@ -31,6 +31,7 @@
#include <asm/msr.h>
#include <asm/segment.h>
#include <asm/processor-flags.h>
+#include "realmode.h"
.text
.balign PAGE_SIZE
@@ -40,9 +41,7 @@ ENTRY(trampoline_data)
cli # We should be safe anyway
wbinvd
- .byte 0xea # ljmpw
- .word 1f # Offset
- .word real_mode_seg # Segment
+ LJMPW_RM(1f)
1:
mov %cs, %ax # Code and data in the same place
mov %ax, %ds
diff --git a/arch/x86/realmode/rm/wakeup/wakeup_asm.S b/arch/x86/realmode/rm/wakeup/wakeup_asm.S
index 4c5c5f2..8064e1c 100644
--- a/arch/x86/realmode/rm/wakeup/wakeup_asm.S
+++ b/arch/x86/realmode/rm/wakeup/wakeup_asm.S
@@ -6,6 +6,7 @@
#include <asm/page_types.h>
#include <asm/pgtable_types.h>
#include <asm/processor-flags.h>
+#include "../realmode.h"
#include "wakeup.h"
.code16
@@ -36,9 +37,7 @@ wakeup_start:
cli
cld
- .byte 0xea /* ljmpw */
- .word 3f
- .word real_mode_seg
+ LJMPW_RM(3f)
3:
/* Apparently some dimwit BIOS programmers don't know how to
program a PM to RM transition, and we might end up here with
@@ -59,9 +58,7 @@ wakeup_start:
andb $~X86_CR0_PE, %al
movl %eax, %cr0
- .byte 0xea /* ljmpw */
- .word 3f
- .word real_mode_seg
+ LJMPW_RM(3f)
3:
/* Set up segments */
movw %cs, %ax
next prev parent reply other threads:[~2012-05-08 22:25 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-08 18:22 [PATCH 00/23] x86, realmode: new infrastructure for realmode code Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 01/23] x86, realmode: 16-bit real-mode code support for relocs tool Jarkko Sakkinen
2012-05-08 22:13 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 02/23] x86, realmode: realmode.bin infrastructure Jarkko Sakkinen
2012-05-08 18:53 ` Sam Ravnborg
2012-05-08 19:14 ` H. Peter Anvin
2012-05-08 20:15 ` H. Peter Anvin
2012-05-08 21:11 ` Sam Ravnborg
2012-05-08 21:21 ` H. Peter Anvin
2012-05-08 22:14 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-09 15:49 ` [PATCH 02/23] " H. Peter Anvin
[not found] ` <alpine.DEB.2.02.1205092256240.31031@jsakkine-mobl1.(null)>
2012-05-09 20:06 ` H. Peter Anvin
2012-05-08 18:22 ` [PATCH 03/23] x86, realmode: Relocator for realmode code Jarkko Sakkinen
2012-05-08 22:15 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 04/23] x86, realmode: Move reboot_32.S to unified " Jarkko Sakkinen
2012-05-08 22:16 ` [tip:x86/trampoline] x86, realmode: Move reboot_32. S " tip-bot for Jarkko Sakkinen
2012-05-09 7:12 ` [PATCH 04/23] x86, realmode: Move reboot_32.S " Paolo Bonzini
[not found] ` <alpine.DEB.2.02.1205091525100.6943@jsakkine-mobl2.(null)>
2012-05-09 13:53 ` H. Peter Anvin
2012-05-09 14:15 ` Paolo Bonzini
2012-05-09 14:18 ` H. Peter Anvin
2012-05-08 18:22 ` [PATCH 05/23] x86, realmode: Move SMP trampoline " Jarkko Sakkinen
2012-05-08 22:17 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 06/23] x86, realmode: Move ACPI wakeup " Jarkko Sakkinen
2012-05-08 22:18 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 07/23] x86, realmode: Set permission for real mode pages Jarkko Sakkinen
2012-05-08 22:19 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 08/23] x86, realmode: Allow absolute pa_* symbols in the realmode code Jarkko Sakkinen
2012-05-08 22:19 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 09/23] x86, realmode: Add .text64 section, make barrier symbols absolute Jarkko Sakkinen
2012-05-08 22:20 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 10/23] x86, realmode: Move bits to the proper sections in trampoline_64.S Jarkko Sakkinen
2012-05-08 22:21 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 11/23] x86, realmode: Align .data section in trampoline_32.S Jarkko Sakkinen
2012-05-08 22:22 ` [tip:x86/trampoline] x86, realmode: Align . data " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 12/23] x86, realmode: Remove indirect jumps in trampoline_64.S Jarkko Sakkinen
2012-05-08 22:23 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 13/23] x86, realmode: Remove indirect jumps in trampoline_32 and wakeup_asm Jarkko Sakkinen
2012-05-08 22:24 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 14/23] x86, realmode: Replace open-coded ljmpw with a macro Jarkko Sakkinen
2012-05-08 22:24 ` tip-bot for H. Peter Anvin [this message]
2012-05-08 18:22 ` [PATCH 15/23] x86, realmode: Move trampoline_*.S early in the link order Jarkko Sakkinen
2012-05-08 22:25 ` [tip:x86/trampoline] x86, realmode: Move trampoline_*. S " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 16/23] x86, realmode: Fix always-zero test in reboot_32.S Jarkko Sakkinen
2012-05-08 22:26 ` [tip:x86/trampoline] " tip-bot for H. Peter Anvin
2012-05-08 18:22 ` [PATCH 17/23] x86, realmode: fix 64-bit wakeup sequence Jarkko Sakkinen
2012-05-08 22:27 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 18/23] x86, realmode: don't copy real_mode_header Jarkko Sakkinen
2012-05-08 22:28 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 19/23] x86, realmode: flattened rm hierachy Jarkko Sakkinen
2012-05-08 22:29 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 20/23] x86, realmode: header for trampoline code Jarkko Sakkinen
2012-05-08 22:29 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 21/23] x86, realmode: move relocs from scripts/ to arch/x86/tools Jarkko Sakkinen
2012-05-08 22:30 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 22/23] x86, realmode: fixes compilation issue in tboot.c Jarkko Sakkinen
2012-05-08 22:31 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-08 18:22 ` [PATCH 23/23] x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline Jarkko Sakkinen
2012-05-08 22:32 ` [tip:x86/trampoline] " tip-bot for Jarkko Sakkinen
2012-05-16 20:37 ` [tip:x86/trampoline] x86, realmode: Mask out EFER. LMA when saving trampoline EFER tip-bot for H. Peter Anvin
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