mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-26 16:35:13 +07:00
0e96f31ea4
"sizeof(x)" is the canonical coding style used in arch/x86 most of the time. Fix the few places that didn't follow the convention. (Also do some whitespace cleanups in a few places while at it.) [ mingo: Rewrote the changelog. ] Signed-off-by: Jordan Borgner <mail@jordan-borgner.de> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181028125828.7rgammkgzep2wpam@JordanDesktop Signed-off-by: Ingo Molnar <mingo@kernel.org>
137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* 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.
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* Memory detection code
|
|
*/
|
|
|
|
#include "boot.h"
|
|
|
|
#define SMAP 0x534d4150 /* ASCII "SMAP" */
|
|
|
|
static int detect_memory_e820(void)
|
|
{
|
|
int count = 0;
|
|
struct biosregs ireg, oreg;
|
|
struct boot_e820_entry *desc = boot_params.e820_table;
|
|
static struct boot_e820_entry buf; /* static so it is zeroed */
|
|
|
|
initregs(&ireg);
|
|
ireg.ax = 0xe820;
|
|
ireg.cx = sizeof(buf);
|
|
ireg.edx = SMAP;
|
|
ireg.di = (size_t)&buf;
|
|
|
|
/*
|
|
* Note: at least one BIOS is known which assumes that the
|
|
* buffer pointed to by one e820 call is the same one as
|
|
* the previous call, and only changes modified fields. Therefore,
|
|
* we use a temporary buffer and copy the results entry by entry.
|
|
*
|
|
* This routine deliberately does not try to account for
|
|
* ACPI 3+ extended attributes. This is because there are
|
|
* BIOSes in the field which report zero for the valid bit for
|
|
* all ranges, and we don't currently make any use of the
|
|
* other attribute bits. Revisit this if we see the extended
|
|
* attribute bits deployed in a meaningful way in the future.
|
|
*/
|
|
|
|
do {
|
|
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 (oreg.eflags & X86_EFLAGS_CF)
|
|
break;
|
|
|
|
/* Some BIOSes stop returning SMAP in the middle of
|
|
the search loop. We don't know exactly how the BIOS
|
|
screwed up the map at that point, we might have a
|
|
partial map, the full map, or complete garbage, so
|
|
just return failure. */
|
|
if (oreg.eax != SMAP) {
|
|
count = 0;
|
|
break;
|
|
}
|
|
|
|
*desc++ = buf;
|
|
count++;
|
|
} while (ireg.ebx && count < ARRAY_SIZE(boot_params.e820_table));
|
|
|
|
return boot_params.e820_entries = count;
|
|
}
|
|
|
|
static int detect_memory_e801(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ax = 0xe801;
|
|
intcall(0x15, &ireg, &oreg);
|
|
|
|
if (oreg.eflags & X86_EFLAGS_CF)
|
|
return -1;
|
|
|
|
/* Do we really need to do this? */
|
|
if (oreg.cx || oreg.dx) {
|
|
oreg.ax = oreg.cx;
|
|
oreg.bx = oreg.dx;
|
|
}
|
|
|
|
if (oreg.ax > 15*1024) {
|
|
return -1; /* Bogus! */
|
|
} else if (oreg.ax == 15*1024) {
|
|
boot_params.alt_mem_k = (oreg.bx << 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)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ah = 0x88;
|
|
intcall(0x15, &ireg, &oreg);
|
|
|
|
boot_params.screen_info.ext_mem_k = oreg.ax;
|
|
|
|
return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */
|
|
}
|
|
|
|
int detect_memory(void)
|
|
{
|
|
int err = -1;
|
|
|
|
if (detect_memory_e820() > 0)
|
|
err = 0;
|
|
|
|
if (!detect_memory_e801())
|
|
err = 0;
|
|
|
|
if (!detect_memory_88())
|
|
err = 0;
|
|
|
|
return err;
|
|
}
|