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SubjectRe: [PATCH v12 1/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC
On Thu, Nov 29, 2018 at 11:20:13AM -0500, Masayoshi Mizuma wrote:
>On Thu, Nov 29, 2018 at 04:16:27PM +0800, Chao Fan wrote:
>> To fix the conflict between KASLR and memory-hotremove, memory
>> information in SRAT table is necessary.
>>
>> ACPI SRAT (System/Static Resource Affinity Table) can show the details
>> about memory ranges, including ranges of memory provided by hot-added
>> memory devices. SRAT table must be introduced by RSDP pointer (Root
>> System Description Pointer). So RSDP should be found firstly.
>>
>> When booting form KEXEC/EFI/BIOS, the methods to find RSDP pointer
>> are different. When booting from KEXEC, 'acpi_rsdp' may have been
>> added to cmdline, so parse the cmdline and find the RSDP pointer.
>>
>> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
>> ---
>> arch/x86/boot/compressed/acpitb.c | 33 +++++++++++++++++++++++++++++++
>> arch/x86/boot/compressed/misc.c | 5 +++++
>> arch/x86/boot/compressed/misc.h | 4 ++++
>> lib/kstrtox.c | 5 +++++
>> 4 files changed, 47 insertions(+)
>> create mode 100644 arch/x86/boot/compressed/acpitb.c
>>
>> diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c
>> new file mode 100644
>> index 000000000000..614c45655cff
>> --- /dev/null
>> +++ b/arch/x86/boot/compressed/acpitb.c
>> @@ -0,0 +1,33 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +#define BOOT_CTYPE_H
>> +#include "misc.h"
>> +#include "error.h"
>> +
>> +#include <linux/efi.h>
>> +#include <asm/efi.h>
>> +#include <linux/numa.h>
>> +#include <linux/acpi.h>
>> +
>> +#define STATIC
>> +#include <linux/decompress/mm.h>
>> +
>> +/* Store the immovable memory regions. */
>> +struct mem_vector immovable_mem[MAX_NUMNODES*2];
>> +#endif
>> +
>> +static acpi_physical_address get_acpi_rsdp(void)
>> +{
>> +#ifdef CONFIG_KEXEC
>> + unsigned long long res;
>> + int len = 0;
>
>> + char *val;
>> +
>> + val = malloc(19);
>> + len = cmdline_find_option("acpi_rsdp", val, 19);
>> + if (len > 0) {
>> + val[len] = 0;
>
> val[len] = '\0';
>
>> + return (acpi_physical_address)kstrtoull(val, 16, &res);
>> + }
>
>I think free() is needed. Or why don't you use stack?

Oh, thanks, will change it
char val[19];

Thanks,
Chao Fan
>
> char val[19];
>
> len = cmdline_find_option("acpi_rsdp", val, sizeof(val));
> if (len > 0) {
> val[len] = '\0';
> return (acpi_physical_address)kstrtoull(val, 16, &res);
> }
>
>Thanks,
>Masa
>
>> + return 0;
>> +#endif
>> +}
>> diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
>> index 8dd1d5ccae58..e51713fe3add 100644
>> --- a/arch/x86/boot/compressed/misc.c
>> +++ b/arch/x86/boot/compressed/misc.c
>> @@ -12,6 +12,7 @@
>> * High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
>> */
>>
>> +#define BOOT_CTYPE_H
>> #include "misc.h"
>> #include "error.h"
>> #include "pgtable.h"
>> @@ -426,3 +427,7 @@ void fortify_panic(const char *name)
>> {
>> error("detected buffer overflow");
>> }
>> +
>> +#ifdef BOOT_STRING
>> +#include "../../../../lib/kstrtox.c"
>> +#endif
>> diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
>> index a1d5918765f3..809c31effa4b 100644
>> --- a/arch/x86/boot/compressed/misc.h
>> +++ b/arch/x86/boot/compressed/misc.h
>> @@ -116,3 +116,7 @@ static inline void console_init(void)
>> void set_sev_encryption_mask(void);
>>
>> #endif
>> +
>> +/* acpitb.c */
>> +#define BOOT_STRING
>> +extern int kstrtoull(const char *s, unsigned int base, unsigned long long *res);
>> diff --git a/lib/kstrtox.c b/lib/kstrtox.c
>> index 1006bf70bf74..a0ac1b2257b8 100644
>> --- a/lib/kstrtox.c
>> +++ b/lib/kstrtox.c
>> @@ -126,6 +126,9 @@ int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
>> }
>> EXPORT_SYMBOL(kstrtoull);
>>
>> +/* Make compressed period code be able to use kstrtoull(). */
>> +#ifndef BOOT_STRING
>> +
>> /**
>> * kstrtoll - convert a string to a long long
>> * @s: The start of the string. The string must be null-terminated, and may also
>> @@ -408,3 +411,5 @@ kstrto_from_user(kstrtou16_from_user, kstrtou16, u16);
>> kstrto_from_user(kstrtos16_from_user, kstrtos16, s16);
>> kstrto_from_user(kstrtou8_from_user, kstrtou8, u8);
>> kstrto_from_user(kstrtos8_from_user, kstrtos8, s8);
>> +
>> +#endif /* BOOT_STRING */
>> --
>> 2.19.1
>>
>>
>>
>
>


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