diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-bugs-AMD-Add-support-to-disable-RDS-on-Fam-15-16.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-bugs-AMD-Add-support-to-disable-RDS-on-Fam-15-16.patch | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-bugs-AMD-Add-support-to-disable-RDS-on-Fam-15-16.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-bugs-AMD-Add-support-to-disable-RDS-on-Fam-15-16.patch new file mode 100644 index 00000000..a79d655d --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0032-x86-bugs-AMD-Add-support-to-disable-RDS-on-Fam-15-16.patch @@ -0,0 +1,200 @@ +From 5066a8fdb740b1c31a315ea7da3a58c8208b15eb Mon Sep 17 00:00:00 2001 +From: David Woodhouse <dwmw@amazon.co.uk> +Date: Sun, 20 May 2018 20:52:05 +0100 +Subject: [PATCH 32/93] x86/bugs/AMD: Add support to disable RDS on + Fam[15,16,17]h if requested + +commit 764f3c21588a059cd783c6ba0734d4db2d72822d upstream + +AMD does not need the Speculative Store Bypass mitigation to be enabled. + +The parameters for this are already available and can be done via MSR +C001_1020. Each family uses a different bit in that MSR for this. + +[ tglx: Expose the bit mask via a variable and move the actual MSR fiddling + into the bugs code as that's the right thing to do and also required + to prepare for dynamic enable/disable ] + +Suggested-by: Borislav Petkov <bp@suse.de> +Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Reviewed-by: Ingo Molnar <mingo@kernel.org> +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/include/asm/cpufeatures.h | 1 + + arch/x86/include/asm/nospec-branch.h | 4 ++++ + arch/x86/kernel/cpu/amd.c | 26 ++++++++++++++++++++++++++ + arch/x86/kernel/cpu/bugs.c | 27 ++++++++++++++++++++++++++- + arch/x86/kernel/cpu/common.c | 4 ++++ + 5 files changed, 61 insertions(+), 1 deletion(-) + +diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h +index 013f3de..8797069 100644 +--- a/arch/x86/include/asm/cpufeatures.h ++++ b/arch/x86/include/asm/cpufeatures.h +@@ -205,6 +205,7 @@ + #define X86_FEATURE_USE_IBPB ( 7*32+21) /* "" Indirect Branch Prediction Barrier enabled */ + #define X86_FEATURE_USE_IBRS_FW ( 7*32+22) /* "" Use IBRS during runtime firmware calls */ + #define X86_FEATURE_SPEC_STORE_BYPASS_DISABLE ( 7*32+23) /* "" Disable Speculative Store Bypass. */ ++#define X86_FEATURE_AMD_RDS (7*32+24) /* "" AMD RDS implementation */ + + /* Virtualization flags: Linux defined, word 8 */ + #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */ +diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h +index 7b9eacf..3a1541c 100644 +--- a/arch/x86/include/asm/nospec-branch.h ++++ b/arch/x86/include/asm/nospec-branch.h +@@ -244,6 +244,10 @@ enum ssb_mitigation { + SPEC_STORE_BYPASS_DISABLE, + }; + ++/* AMD specific Speculative Store Bypass MSR data */ ++extern u64 x86_amd_ls_cfg_base; ++extern u64 x86_amd_ls_cfg_rds_mask; ++ + extern char __indirect_thunk_start[]; + extern char __indirect_thunk_end[]; + +diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c +index 747f8a2..7551d9ad 100644 +--- a/arch/x86/kernel/cpu/amd.c ++++ b/arch/x86/kernel/cpu/amd.c +@@ -9,6 +9,7 @@ + #include <asm/processor.h> + #include <asm/apic.h> + #include <asm/cpu.h> ++#include <asm/nospec-branch.h> + #include <asm/smp.h> + #include <asm/pci-direct.h> + #include <asm/delay.h> +@@ -542,6 +543,26 @@ static void bsp_init_amd(struct cpuinfo_x86 *c) + rdmsrl(MSR_FAM10H_NODE_ID, value); + nodes_per_socket = ((value >> 3) & 7) + 1; + } ++ ++ if (c->x86 >= 0x15 && c->x86 <= 0x17) { ++ unsigned int bit; ++ ++ switch (c->x86) { ++ case 0x15: bit = 54; break; ++ case 0x16: bit = 33; break; ++ case 0x17: bit = 10; break; ++ default: return; ++ } ++ /* ++ * Try to cache the base value so further operations can ++ * avoid RMW. If that faults, do not enable RDS. ++ */ ++ if (!rdmsrl_safe(MSR_AMD64_LS_CFG, &x86_amd_ls_cfg_base)) { ++ setup_force_cpu_cap(X86_FEATURE_RDS); ++ setup_force_cpu_cap(X86_FEATURE_AMD_RDS); ++ x86_amd_ls_cfg_rds_mask = 1ULL << bit; ++ } ++ } + } + + static void early_init_amd(struct cpuinfo_x86 *c) +@@ -827,6 +848,11 @@ static void init_amd(struct cpuinfo_x86 *c) + /* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */ + if (!cpu_has(c, X86_FEATURE_XENPV)) + set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); ++ ++ if (boot_cpu_has(X86_FEATURE_AMD_RDS)) { ++ set_cpu_cap(c, X86_FEATURE_RDS); ++ set_cpu_cap(c, X86_FEATURE_AMD_RDS); ++ } + } + + #ifdef CONFIG_X86_32 +diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c +index b92c469..b3696cc 100644 +--- a/arch/x86/kernel/cpu/bugs.c ++++ b/arch/x86/kernel/cpu/bugs.c +@@ -40,6 +40,13 @@ static u64 __ro_after_init x86_spec_ctrl_base; + */ + static u64 __ro_after_init x86_spec_ctrl_mask = ~SPEC_CTRL_IBRS; + ++/* ++ * AMD specific MSR info for Speculative Store Bypass control. ++ * x86_amd_ls_cfg_rds_mask is initialized in identify_boot_cpu(). ++ */ ++u64 __ro_after_init x86_amd_ls_cfg_base; ++u64 __ro_after_init x86_amd_ls_cfg_rds_mask; ++ + void __init check_bugs(void) + { + identify_boot_cpu(); +@@ -51,7 +58,8 @@ void __init check_bugs(void) + + /* + * Read the SPEC_CTRL MSR to account for reserved bits which may +- * have unknown values. ++ * have unknown values. AMD64_LS_CFG MSR is cached in the early AMD ++ * init code as it is not enumerated and depends on the family. + */ + if (boot_cpu_has(X86_FEATURE_IBRS)) + rdmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base); +@@ -153,6 +161,14 @@ void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl) + } + EXPORT_SYMBOL_GPL(x86_spec_ctrl_restore_host); + ++static void x86_amd_rds_enable(void) ++{ ++ u64 msrval = x86_amd_ls_cfg_base | x86_amd_ls_cfg_rds_mask; ++ ++ if (boot_cpu_has(X86_FEATURE_AMD_RDS)) ++ wrmsrl(MSR_AMD64_LS_CFG, msrval); ++} ++ + #ifdef RETPOLINE + static bool spectre_v2_bad_module; + +@@ -442,6 +458,11 @@ static enum ssb_mitigation_cmd __init __ssb_select_mitigation(void) + + switch (cmd) { + case SPEC_STORE_BYPASS_CMD_AUTO: ++ /* ++ * AMD platforms by default don't need SSB mitigation. ++ */ ++ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) ++ break; + case SPEC_STORE_BYPASS_CMD_ON: + mode = SPEC_STORE_BYPASS_DISABLE; + break; +@@ -468,6 +489,7 @@ static enum ssb_mitigation_cmd __init __ssb_select_mitigation(void) + x86_spec_ctrl_set(SPEC_CTRL_RDS); + break; + case X86_VENDOR_AMD: ++ x86_amd_rds_enable(); + break; + } + } +@@ -489,6 +511,9 @@ void x86_spec_ctrl_setup_ap(void) + { + if (boot_cpu_has(X86_FEATURE_IBRS)) + x86_spec_ctrl_set(x86_spec_ctrl_base & ~x86_spec_ctrl_mask); ++ ++ if (ssb_mode == SPEC_STORE_BYPASS_DISABLE) ++ x86_amd_rds_enable(); + } + + #ifdef CONFIG_SYSFS +diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c +index ab6b3ad..beb1da8 100644 +--- a/arch/x86/kernel/cpu/common.c ++++ b/arch/x86/kernel/cpu/common.c +@@ -895,6 +895,10 @@ static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = { + { X86_VENDOR_CENTAUR, 5, }, + { X86_VENDOR_INTEL, 5, }, + { X86_VENDOR_NSC, 5, }, ++ { X86_VENDOR_AMD, 0x12, }, ++ { X86_VENDOR_AMD, 0x11, }, ++ { X86_VENDOR_AMD, 0x10, }, ++ { X86_VENDOR_AMD, 0xf, }, + { X86_VENDOR_ANY, 4, }, + {} + }; +-- +2.7.4 + |