On Thu, Dec 13, 2018 at 02:25:30PM -0500, Masayoshi Mizuma wrote: >Hi Chao, > >Great work! Let me say some trivial comments.
Thanks for your help, any comments will be welcome. > >On Wed, Dec 12, 2018 at 11:10:49AM +0800, Chao Fan wrote: >> Memory information in SRAT is necessary to fix the conflict between >> KASLR and memory-hotremove. >> >> ACPI SRAT (System/Static Resource Affinity Table) shows the details >> about memory ranges, including ranges of memory provided by hot-added >> memory devices. SRAT is introduced by Root System Description >> Pointer(RSDP). So RSDP should be found firstly. >> >> When booting form KEXEC/EFI/BIOS, the methods to find RSDP >> are different. When booting from KEXEC, 'acpi_rsdp' may have been >> added to cmdline, so parse cmdline to find RSDP. >> >> Since 'RANDOMIZE_BASE' && 'MEMORY_HOTREMOVE' is needed, introduce >> 'CONFIG_EARLY_PARSE_RSDP' to make ifdeffery clear. >> >> Signed-off-by: Chao Fan <fanc.f...@cn.fujitsu.com> >> --- >> arch/x86/Kconfig | 10 ++++++++++ >> arch/x86/boot/compressed/acpi.c | 30 ++++++++++++++++++++++++++++++ >> arch/x86/boot/compressed/misc.h | 6 ++++++ >> 3 files changed, 46 insertions(+) >> create mode 100644 arch/x86/boot/compressed/acpi.c >> >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >> index ba7e3464ee92..455da382fa9e 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -2149,6 +2149,16 @@ config X86_NEED_RELOCS >> def_bool y >> depends on RANDOMIZE_BASE || (X86_32 && RELOCATABLE) >> >> +config EARLY_PARSE_RSDP >> + bool "Parse RSDP pointer on compressed period for KASLR" >> + def_bool y >> + depends on RANDOMIZE_BASE && MEMORY_HOTREMOVE >> + help >> + This option parses RSDP in compressed period. Works >> + for KASLR to get memory information from SRAT table and choose >> + immovable memory to extract kernel. >> + Say Y if you want to use both KASLR and memory-hotremove. >> + >> config PHYSICAL_ALIGN >> hex "Alignment value to which kernel should be aligned" >> default "0x200000" >> diff --git a/arch/x86/boot/compressed/acpi.c >> b/arch/x86/boot/compressed/acpi.c >> new file mode 100644 >> index 000000000000..cad15686f82c >> --- /dev/null >> +++ b/arch/x86/boot/compressed/acpi.c >> @@ -0,0 +1,30 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +#define BOOT_CTYPE_H >> +#include "misc.h" >> +#include "error.h" >> + >> +#include <linux/efi.h> >> +#include <linux/numa.h> >> +#include <linux/acpi.h> >> +#include <asm/efi.h> >> + >> +#define STATIC >> +#include <linux/decompress/mm.h> >> + >> +#include "../string.h" >> + >> +static acpi_physical_address get_acpi_rsdp(void) >> +{ >> +#ifdef CONFIG_KEXEC >> + unsigned long long res; >> + int len = 0; >> + char val[MAX_ADDRESS_LENGTH+1]; >> + > >> + len = cmdline_find_option("acpi_rsdp", val, MAX_ADDRESS_LENGTH+1); > >sizeof() is better here. > > len = cmdline_find_option("acpi_rsdp", val, sizeof(var)); > >> + if (len > 0) { >> + val[len] = 0; > >'\0' should be fine here not 0. > > val[len] = '\0'; Will change it. Thanks, Chao Fan > >> + return (acpi_physical_address)kstrtoull(val, 16, &res); >> + } >> + return 0; >> +#endif >> +} >> diff --git a/arch/x86/boot/compressed/misc.h >> b/arch/x86/boot/compressed/misc.h >> index a1d5918765f3..72fcfbfec3c6 100644 >> --- a/arch/x86/boot/compressed/misc.h >> +++ b/arch/x86/boot/compressed/misc.h >> @@ -116,3 +116,9 @@ static inline void console_init(void) >> void set_sev_encryption_mask(void); >> >> #endif >> + >> +/* acpi.c */ >> +#ifdef CONFIG_EARLY_PARSE_RSDP >> +/* Max length of 64-bit hex address string is 18, prefix "0x" + 16 hex >> digit. */ >> +#define MAX_ADDRESS_LENGTH 18 >> +#endif >> -- >> 2.19.2 >> >> > >