It is useful to obtain the results of MSR queries as well as to update MSR registers, so add a command these tasks.
Signed-off-by: Simon Glass sjg@chromium.org ---
cmd/x86/Makefile | 2 +- cmd/x86/msr.c | 52 ++++++++++++++++++++++++++++++++++++ doc/usage/cmd/msr.rst | 61 +++++++++++++++++++++++++++++++++++++++++++ doc/usage/index.rst | 1 + test/cmd/Makefile | 2 +- test/cmd/msr.c | 38 +++++++++++++++++++++++++++ 6 files changed, 154 insertions(+), 2 deletions(-) create mode 100644 cmd/x86/msr.c create mode 100644 doc/usage/cmd/msr.rst create mode 100644 test/cmd/msr.c
diff --git a/cmd/x86/Makefile b/cmd/x86/Makefile index 1648907ac2d..925215235d3 100644 --- a/cmd/x86/Makefile +++ b/cmd/x86/Makefile @@ -1,7 +1,7 @@ # SPDX-License-Identifier: GPL-2.0+
obj-$(CONFIG_CMD_CBSYSINFO) += cbsysinfo.o -obj-y += cpuid.o mtrr.o +obj-y += cpuid.o msr.o mtrr.o obj-$(CONFIG_CMD_EXCEPTION) += exception.o obj-$(CONFIG_USE_HOB) += hob.o obj-$(CONFIG_HAVE_FSP) += fsp.o diff --git a/cmd/x86/msr.c b/cmd/x86/msr.c new file mode 100644 index 00000000000..3cb70d1f89a --- /dev/null +++ b/cmd/x86/msr.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * The 'cpuid' command provides access to the CPU's cpuid information + * + * Copyright 2024 Google, LLC + * Written by Simon Glass sjg@chromium.org + */ + +#include <command.h> +#include <vsprintf.h> +#include <asm/msr.h> + +static int do_read(struct cmd_tbl *cmdtp, int flag, int argc, + char *const argv[]) +{ + struct msr_t msr; + ulong op; + + if (argc < 2) + return CMD_RET_USAGE; + + op = hextoul(argv[1], NULL); + msr = msr_read(op); + printf("%08x %08x\n", msr.hi, msr.lo); + + return 0; +} + +static int do_write(struct cmd_tbl *cmdtp, int flag, int argc, + char *const argv[]) +{ + struct msr_t msr; + ulong op; + + if (argc < 4) + return CMD_RET_USAGE; + + op = hextoul(argv[1], NULL); + msr.hi = hextoul(argv[2], NULL); + msr.lo = hextoul(argv[3], NULL); + msr_write(op, msr); + + return 0; +} + +U_BOOT_LONGHELP(msr, + "read <op> - read a machine-status register (MSR) as <hi 32-bits> <lo 32-bits>\n" + "write <op< <hi> <lo> - write an MSR"); + +U_BOOT_CMD_WITH_SUBCMDS(msr, "Machine Status Registers", msr_help_text, + U_BOOT_CMD_MKENT(read, CONFIG_SYS_MAXARGS, 1, do_read, "", ""), + U_BOOT_CMD_MKENT(write, CONFIG_SYS_MAXARGS, 1, do_write, "", "")); diff --git a/doc/usage/cmd/msr.rst b/doc/usage/cmd/msr.rst new file mode 100644 index 00000000000..04ee52cc1c7 --- /dev/null +++ b/doc/usage/cmd/msr.rst @@ -0,0 +1,61 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +.. index:: + single: msr (command) + +msr command +=========== + +Synopsis +-------- + +:: + + msr read <op> + msr write <op> <hi> <lo> + +Description +----------- + +The msr command reads and writes machine-status registers (MSRs) on x86 CPUs. +The information is a 64-bit value split into two parts, <hi> for the top 32 +bits and <lo> for the bottom 32 bits. + +The operation <op> selects what information is read or written. + +msr read +~~~~~~~~ + +This reads an MSR and displays the value obtained. + +msr write +~~~~~~~~~ + +This writes a value to an MSR. + +Configuration +------------- + +The msr command is only available on x86. + +Return value +------------ + +The return value $? is 0 (true). + +Example +------- + +This shows reading msr 0x194 which is MSR_FLEX_RATIO on Intel CPUs:: + + => msr read 194 + 00000000 00011200 # Bits 16 (flex ratio enable) and 20 (lock) are set + +This shows adjusting the energy-performance bias on an Intel CPU:: + + => msr read 1b0 + 00000000 00000006 # 6 means 'normal' + + => msr write 1b0 0 f # change to power-save + => msr read 1b0 + 00000000 0000000f diff --git a/doc/usage/index.rst b/doc/usage/index.rst index 986554090af..2e60afb297e 100644 --- a/doc/usage/index.rst +++ b/doc/usage/index.rst @@ -87,6 +87,7 @@ Shell commands cmd/mbr cmd/md cmd/mmc + cmd/msr cmd/mtest cmd/mtrr cmd/panic diff --git a/test/cmd/Makefile b/test/cmd/Makefile index dedcec33c8e..fb6795a87a5 100644 --- a/test/cmd/Makefile +++ b/test/cmd/Makefile @@ -12,7 +12,7 @@ ifdef CONFIG_CONSOLE_RECORD obj-$(CONFIG_CMD_PAUSE) += test_pause.o endif obj-y += exit.o mem.o -obj-$(CONFIG_X86) += cpuid.o +obj-$(CONFIG_X86) += cpuid.o msr.o obj-$(CONFIG_CMD_ADDRMAP) += addrmap.o obj-$(CONFIG_CMD_BDI) += bdinfo.o obj-$(CONFIG_CMD_FDT) += fdt.o diff --git a/test/cmd/msr.c b/test/cmd/msr.c new file mode 100644 index 00000000000..e9a152ee5bf --- /dev/null +++ b/test/cmd/msr.c @@ -0,0 +1,38 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Tests for msr command + * + * Copyright 2024 Google LLC + * Written by Simon Glass sjg@chromium.org + */ + +#include <test/cmd.h> +#include <test/ut.h> + +static int cmd_test_msr(struct unit_test_state *uts) +{ + ut_assertok(run_commandf("msr read 200")); + ut_assert_nextline("00000000 ffe00006"); + ut_assert_console_end(); + + /* change the first variable msr and see it reflected in the mtrr cmd */ + ut_assertok(run_commandf("mtrr")); + ut_assert_nextline("CPU 65537:"); + ut_assert_nextlinen("Reg"); + ut_assert_nextlinen("0 Y Back 00000000ffe00000"); + ut_assertok(console_record_reset_enable()); + + /* change the type from 6 to 5 */ + ut_assertok(run_commandf("msr write 200 0 ffe00005")); + ut_assert_console_end(); + + /* Now it shows 'Protect' */ + ut_assertok(run_commandf("mtrr")); + ut_assert_nextline("CPU 65537:"); + ut_assert_nextlinen("Reg"); + ut_assert_nextlinen("0 Y Protect 00000000ffe00000"); + ut_assertok(console_record_reset_enable()); + + return 0; +} +CMD_TEST(cmd_test_msr, UTF_CONSOLE);