diff options
| author | Arthur Heymans <arthur@aheymans.xyz> | 2022-04-19 20:48:42 +0200 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2022-04-25 14:00:41 +0000 |
| commit | 597b9e9d71a2dd728e4192fa9a083004c96cdfbc (patch) | |
| tree | 02a1e721719751f6968eeeae0692d19099dd23c6 /src/cpu | |
| parent | 34f5cd9cb233dea539a94ff2cc8c06effced988d (diff) | |
cpu/x86/64bit: Generate static page tables from an assembly file
This removes the need for a tool to generate simple identity pages.
Future patches will link this page table directly into the stages on
some platforms so having an assembly file makes a lot of sense.
This also optimizes the size of the page of each 4K page by placing
the PDPE_table below the PDE.
Change-Id: Ia1e31b701a2584268c85d327bf139953213899e3
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63725
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Diffstat (limited to 'src/cpu')
| -rw-r--r-- | src/cpu/x86/64bit/Makefile.inc | 12 | ||||
| -rw-r--r-- | src/cpu/x86/64bit/pt.S | 35 |
2 files changed, 47 insertions, 0 deletions
diff --git a/src/cpu/x86/64bit/Makefile.inc b/src/cpu/x86/64bit/Makefile.inc index 721e62044d..1895498111 100644 --- a/src/cpu/x86/64bit/Makefile.inc +++ b/src/cpu/x86/64bit/Makefile.inc @@ -5,3 +5,15 @@ endif romstage-y += mode_switch.S postcar-y += mode_switch.S ramstage-y += mode_switch.S + +# Add --defsym=_start=0 to suppress a linker warning. +$(objcbfs)/pt: $(dir)/pt.S + $(CC_bootblock) $(CFLAGS_bootblock) $(CPPFLAGS_bootblock) -o $@.tmp $< -Wl,--section-start=.rodata=$(CONFIG_ARCH_X86_64_PGTBL_LOC),--defsym=_start=0 + $(OBJCOPY_ramstage) -Obinary -j .rodata $@.tmp $@ + rm $@.tmp + +cbfs-files-y += pagetables +pagetables-file := $(objcbfs)/pt +pagetables-type := raw +pagetables-compression := none +pagetables-COREBOOT-position := $(CONFIG_ARCH_X86_64_PGTBL_LOC) diff --git a/src/cpu/x86/64bit/pt.S b/src/cpu/x86/64bit/pt.S new file mode 100644 index 0000000000..b105528e5e --- /dev/null +++ b/src/cpu/x86/64bit/pt.S @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/* + * For reference see "AMD64 Architecture Programmer's Manual Volume 2", + * Document 24593-Rev. 3.31-July 2019 Chapter 5.3.4 + * + * Page table attributes: WB, User+Supervisor, Present, Writeable, Accessed, Dirty + */ + +.section .rodata +#define _PRES (1ULL << 0) +#define _RW (1ULL << 1) +#define _US (1ULL << 2) +#define _A (1ULL << 5) +#define _D (1ULL << 6) +#define _PS (1ULL << 7) +#define _GEN_DIR(a) (_PRES + _RW + _US + _A + (a)) +#define _GEN_PAGE(a) (_PRES + _RW + _US + _PS + _A + _D + (a)) + +.global PM4LE +.align 32 +PM4LE: +.quad _GEN_DIR(PDPE_table) + +.align 4096 +PDE_tables: /* identity map 2MiB pages */ +.rept 2048 +.quad _GEN_PAGE(0x200000 * ((. - PDE_tables) >> 3)) +.endr + +.align 4096 +PDPE_table: /* Point to PDE */ +.rept 4 +.quad _GEN_DIR(PDE_tables + 4096 * ((. - PDPE_table) >> 3)) +.endr |