Messages in this thread | | | Date | Fri, 11 Jan 2019 09:27:18 +0800 | From | Chao Fan <> | Subject | Re: [PATCH v15 4/6] x86/boot: Introduce bios_get_rsdp_addr() to search RSDP in memory |
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On Thu, Jan 10, 2019 at 10:27:47PM +0100, Borislav Petkov wrote: >On Mon, Jan 07, 2019 at 11:22:41AM +0800, Chao Fan wrote: >> Memory information in SRAT table is necessary to fix the conflict >> between KASLR and memory-hotremove. So RSDP and SRAT should be parsed. >> >> When booting form KEXEC/EFI/BIOS, the methods to compute RSDP >> are different. When booting from BIOS, there is no variable who can >> point to RSDP directly, so scan memory for the RSDP and verify RSDP >> by signature and checksum. >> >> Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com> >> --- >> arch/x86/boot/compressed/acpi.c | 86 +++++++++++++++++++++++++++++++++ >> 1 file changed, 86 insertions(+) > >... > >> +/* Search RSDP address, based on acpi_find_root_pointer(). */ >> +static acpi_physical_address bios_get_rsdp_addr(void) >> +{ >> + u8 *table_ptr; >> + u32 address; >> + u8 *rsdp; > >But those u8's together: > > u8 *table_ptr, *rsdp; > u32 address;
Thanks, will change that.
> >> + >> + /* Get the location of the Extended BIOS Data Area (EBDA) */ >> + table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION; >> + address = *(u16 *)table_ptr; >> + address <<= 4; >> + table_ptr = (u8 *)(long)address; >> + >> + /* >> + * Search EBDA paragraphs (EBDA is required to be a minimum of >> + * 1K length) >> + */ >> + if (address > 0x400) { >> + rsdp = scan_mem_for_rsdp(table_ptr, ACPI_EBDA_WINDOW_SIZE); >> + if (rsdp) { >> + address += (u32)ACPI_PTR_DIFF(rsdp, table_ptr); >> + return address; >> + } >> + } >> + >> + /* Search upper memory: 16-byte boundaries in E0000h-FFFFFh */ >> + table_ptr = (u8 *)ACPI_HI_RSDP_WINDOW_BASE; >> + rsdp = scan_mem_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); >> + > >Superfluous newline.
Will drop it.
Thanks, Chao Fan
> >> + if (rsdp) { >> + address = (u32)(ACPI_HI_RSDP_WINDOW_BASE + >> + ACPI_PTR_DIFF(rsdp, table_ptr)); >> + return address; >> + } >> + return 0; >> +} > >-- >Regards/Gruss, > Boris. > >Good mailing practices for 400: avoid top-posting and trim the reply. > >
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