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Date: Thu, 9 Apr 2009 23:13:00 GMT
From: "H. Peter Anvin" <hpa@...ux.intel.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the core boot code
Commit-ID: df7699c56421c0476704f24a43409ac8c505f3d2
Gitweb: http://git.kernel.org/tip/df7699c56421c0476704f24a43409ac8c505f3d2
Author: H. Peter Anvin <hpa@...ux.intel.com>
AuthorDate: Wed, 1 Apr 2009 18:13:46 -0700
Committer: H. Peter Anvin <hpa@...or.com>
CommitDate: Thu, 9 Apr 2009 16:08:11 -0700
x86, setup: "glove box" BIOS interrupts in the core boot code
Impact: BIOS proofing
"Glove box" off BIOS interrupts in the core boot code.
LKML-Reference: <49DE7F79.4030106@...or.com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
arch/x86/boot/a20.c | 9 +++--
arch/x86/boot/main.c | 39 ++++++++++++----------
arch/x86/boot/memory.c | 81 +++++++++++++++++++++++------------------------
arch/x86/boot/tty.c | 52 ++++++++++++++++--------------
4 files changed, 95 insertions(+), 86 deletions(-)
diff --git a/arch/x86/boot/a20.c b/arch/x86/boot/a20.c
index 7c19ce8..64a31a6 100644
--- a/arch/x86/boot/a20.c
+++ b/arch/x86/boot/a20.c
@@ -2,7 +2,7 @@
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
- * Copyright 2009 Intel Corporation
+ * Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@@ -90,8 +90,11 @@ static int a20_test_long(void)
static void enable_a20_bios(void)
{
- asm volatile("pushfl; int $0x15; popfl"
- : : "a" ((u16)0x2401));
+ struct biosregs ireg;
+
+ initregs(&ireg);
+ ireg.ax = 0x2401;
+ intcall(0x15, &ireg, NULL);
}
static void enable_a20_kbc(void)
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index 58f0415..140172b 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -2,6 +2,7 @@
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@@ -61,11 +62,10 @@ static void copy_boot_params(void)
*/
static void keyboard_set_repeat(void)
{
- u16 ax = 0x0305;
- u16 bx = 0;
- asm volatile("int $0x16"
- : "+a" (ax), "+b" (bx)
- : : "ecx", "edx", "esi", "edi");
+ struct biosregs ireg;
+ initregs(&ireg);
+ ireg.ax = 0x0305;
+ intcall(0x16, &ireg, NULL);
}
/*
@@ -73,18 +73,22 @@ static void keyboard_set_repeat(void)
*/
static void query_ist(void)
{
+ struct biosregs ireg, oreg;
+
/* Some older BIOSes apparently crash on this call, so filter
it from machines too old to have SpeedStep at all. */
if (cpu.level < 6)
return;
- asm("int $0x15"
- : "=a" (boot_params.ist_info.signature),
- "=b" (boot_params.ist_info.command),
- "=c" (boot_params.ist_info.event),
- "=d" (boot_params.ist_info.perf_level)
- : "a" (0x0000e980), /* IST Support */
- "d" (0x47534943)); /* Request value */
+ initregs(&ireg);
+ ireg.ax = 0xe980; /* IST Support */
+ ireg.edx = 0x47534943; /* Request value */
+ intcall(0x15, &ireg, &oreg);
+
+ boot_params.ist_info.signature = oreg.eax;
+ boot_params.ist_info.command = oreg.ebx;
+ boot_params.ist_info.event = oreg.ecx;
+ boot_params.ist_info.perf_level = oreg.edx;
}
/*
@@ -93,13 +97,12 @@ static void query_ist(void)
static void set_bios_mode(void)
{
#ifdef CONFIG_X86_64
- u32 eax, ebx;
+ struct biosregs ireg;
- eax = 0xec00;
- ebx = 2;
- asm volatile("int $0x15"
- : "+a" (eax), "+b" (ebx)
- : : "ecx", "edx", "esi", "edi");
+ initregs(&ireg);
+ ireg.ax = 0xec00;
+ ireg.bx = 2;
+ intcall(0x15, &ireg, NULL);
#endif
}
diff --git a/arch/x86/boot/memory.c b/arch/x86/boot/memory.c
index 5054c2d..d989de8 100644
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@ -25,12 +25,16 @@ struct e820_ext_entry {
static int detect_memory_e820(void)
{
int count = 0;
- u32 next = 0;
- u32 size, id, edi;
- u8 err;
+ struct biosregs ireg, oreg;
struct e820entry *desc = boot_params.e820_map;
static struct e820_ext_entry buf; /* static so it is zeroed */
+ initregs(&ireg);
+ ireg.ax = 0xe820;
+ ireg.cx = sizeof buf;
+ ireg.edx = SMAP;
+ ireg.di = (size_t)&buf;
+
/*
* Set this here so that if the BIOS doesn't change this field
* but still doesn't change %ecx, we're still okay...
@@ -38,22 +42,13 @@ static int detect_memory_e820(void)
buf.ext_flags = 1;
do {
- size = sizeof buf;
-
- /* Important: %edx and %esi are clobbered by some BIOSes,
- so they must be either used for the error output
- or explicitly marked clobbered. Given that, assume there
- is something out there clobbering %ebp and %edi, too. */
- asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"
- : "=d" (err), "+b" (next), "=a" (id), "+c" (size),
- "=D" (edi), "+m" (buf)
- : "D" (&buf), "d" (SMAP), "a" (0xe820)
- : "esi");
+ intcall(0x15, &ireg, &oreg);
+ ireg.ebx = oreg.ebx; /* for next iteration... */
/* BIOSes which terminate the chain with CF = 1 as opposed
to %ebx = 0 don't always report the SMAP signature on
the final, failing, probe. */
- if (err)
+ if (oreg.eflags & X86_EFLAGS_CF)
break;
/* Some BIOSes stop returning SMAP in the middle of
@@ -61,7 +56,7 @@ static int detect_memory_e820(void)
screwed up the map at that point, we might have a
partial map, the full map, or complete garbage, so
just return failure. */
- if (id != SMAP) {
+ if (oreg.eax != SMAP) {
count = 0;
break;
}
@@ -69,58 +64,62 @@ static int detect_memory_e820(void)
/* ACPI 3.0 added the extended flags support. If bit 0
in the extended flags is zero, we're supposed to simply
ignore the entry -- a backwards incompatible change! */
- if (size > 20 && !(buf.ext_flags & 1))
+ if (oreg.cx > 20 && !(buf.ext_flags & 1))
continue;
*desc++ = buf.std;
count++;
- } while (next && count < ARRAY_SIZE(boot_params.e820_map));
+ } while (ireg.ebx && count < ARRAY_SIZE(boot_params.e820_map));
return boot_params.e820_entries = count;
}
static int detect_memory_e801(void)
{
- u16 ax, bx, cx, dx;
- u8 err;
+ struct biosregs ireg, oreg;
- bx = cx = dx = 0;
- ax = 0xe801;
- asm("stc; int $0x15; setc %0"
- : "=m" (err), "+a" (ax), "+b" (bx), "+c" (cx), "+d" (dx));
+ initregs(&ireg);
+ ireg.ax = 0xe801;
+ intcall(0x15, &ireg, &oreg);
- if (err)
+ if (oreg.eflags & X86_EFLAGS_CF)
return -1;
/* Do we really need to do this? */
- if (cx || dx) {
- ax = cx;
- bx = dx;
+ if (oreg.cx || oreg.dx) {
+ oreg.ax = oreg.cx;
+ oreg.bx = oreg.dx;
}
- if (ax > 15*1024)
+ if (oreg.ax > 15*1024) {
return -1; /* Bogus! */
-
- /* This ignores memory above 16MB if we have a memory hole
- there. If someone actually finds a machine with a memory
- hole at 16MB and no support for 0E820h they should probably
- generate a fake e820 map. */
- boot_params.alt_mem_k = (ax == 15*1024) ? (dx << 6)+ax : ax;
+ } else if (oreg.ax == 15*1024) {
+ boot_params.alt_mem_k = (oreg.dx << 6) + oreg.ax;
+ } else {
+ /*
+ * This ignores memory above 16MB if we have a memory
+ * hole there. If someone actually finds a machine
+ * with a memory hole at 16MB and no support for
+ * 0E820h they should probably generate a fake e820
+ * map.
+ */
+ boot_params.alt_mem_k = oreg.ax;
+ }
return 0;
}
static int detect_memory_88(void)
{
- u16 ax;
- u8 err;
+ struct biosregs ireg, oreg;
- ax = 0x8800;
- asm("stc; int $0x15; setc %0" : "=bcdm" (err), "+a" (ax));
+ initregs(&ireg);
+ ireg.ah = 0x88;
+ intcall(0x15, &ireg, &oreg);
- boot_params.screen_info.ext_mem_k = ax;
+ boot_params.screen_info.ext_mem_k = oreg.ax;
- return -err;
+ return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */
}
int detect_memory(void)
diff --git a/arch/x86/boot/tty.c b/arch/x86/boot/tty.c
index 7e8e8b2..01ec69c 100644
--- a/arch/x86/boot/tty.c
+++ b/arch/x86/boot/tty.c
@@ -2,6 +2,7 @@
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@@ -22,24 +23,23 @@
void __attribute__((section(".inittext"))) putchar(int ch)
{
- unsigned char c = ch;
+ struct biosregs ireg;
- if (c == '\n')
+ if (ch == '\n')
putchar('\r'); /* \n -> \r\n */
- /* int $0x10 is known to have bugs involving touching registers
- it shouldn't. Be extra conservative... */
- asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal"
- : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));
+ initregs(&ireg);
+ ireg.bx = 0x0007;
+ ireg.cx = 0x0001;
+ ireg.ah = 0x0e;
+ ireg.al = ch;
+ intcall(0x10, &ireg, NULL);
}
void __attribute__((section(".inittext"))) puts(const char *str)
{
- int n = 0;
- while (*str) {
+ while (*str)
putchar(*str++);
- n++;
- }
}
/*
@@ -49,14 +49,13 @@ void __attribute__((section(".inittext"))) puts(const char *str)
static u8 gettime(void)
{
- u16 ax = 0x0200;
- u16 cx, dx;
+ struct biosregs ireg, oreg;
- asm volatile("int $0x1a"
- : "+a" (ax), "=c" (cx), "=d" (dx)
- : : "ebx", "esi", "edi");
+ initregs(&ireg);
+ ireg.ah = 0x02;
+ intcall(0x1a, &ireg, &oreg);
- return dx >> 8;
+ return oreg.dh;
}
/*
@@ -64,19 +63,24 @@ static u8 gettime(void)
*/
int getchar(void)
{
- u16 ax = 0;
- asm volatile("int $0x16" : "+a" (ax));
+ struct biosregs ireg, oreg;
+
+ initregs(&ireg);
+ /* ireg.ah = 0x00; */
+ intcall(0x16, &ireg, &oreg);
- return ax & 0xff;
+ return oreg.al;
}
static int kbd_pending(void)
{
- u8 pending;
- asm volatile("int $0x16; setnz %0"
- : "=qm" (pending)
- : "a" (0x0100));
- return pending;
+ struct biosregs ireg, oreg;
+
+ initregs(&ireg);
+ ireg.ah = 0x01;
+ intcall(0x16, &ireg, &oreg);
+
+ return !(oreg.eflags & X86_EFLAGS_ZF);
}
void kbd_flush(void)
--
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