mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-16 22:56:44 +07:00
97873a3daf
Based on 1 normalized pattern(s): this file is part of the linux kernel and is made available under the terms of the gnu general public license version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 28 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.534229504@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/* -*- linux-c -*- ------------------------------------------------------- *
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright 2007 rPath, Inc. - All Rights Reserved
|
|
* Copyright 2009 Intel Corporation; author H. Peter Anvin
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* Memory detection code
|
|
*/
|
|
|
|
#include "boot.h"
|
|
|
|
#define SMAP 0x534d4150 /* ASCII "SMAP" */
|
|
|
|
static void 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));
|
|
|
|
boot_params.e820_entries = count;
|
|
}
|
|
|
|
static void detect_memory_e801(void)
|
|
{
|
|
struct biosregs ireg, oreg;
|
|
|
|
initregs(&ireg);
|
|
ireg.ax = 0xe801;
|
|
intcall(0x15, &ireg, &oreg);
|
|
|
|
if (oreg.eflags & X86_EFLAGS_CF)
|
|
return;
|
|
|
|
/* 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; /* 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;
|
|
}
|
|
}
|
|
|
|
static void 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;
|
|
}
|
|
|
|
void detect_memory(void)
|
|
{
|
|
detect_memory_e820();
|
|
|
|
detect_memory_e801();
|
|
|
|
detect_memory_88();
|
|
}
|