From 23fa18eaa71266feff7ba8d83022d9e1cc83c65a Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:42:03 +0000
Subject: [PATCH] disable pwm7
---
kernel/arch/powerpc/kernel/security.c | 225 ++++++++++++++++++++++++++++++++++++++-----------------
1 files changed, 155 insertions(+), 70 deletions(-)
diff --git a/kernel/arch/powerpc/kernel/security.c b/kernel/arch/powerpc/kernel/security.c
index 48985a1..3f510c9 100644
--- a/kernel/arch/powerpc/kernel/security.c
+++ b/kernel/arch/powerpc/kernel/security.c
@@ -7,6 +7,8 @@
#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/device.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
#include <linux/seq_buf.h>
#include <asm/asm-prototypes.h>
@@ -14,17 +16,18 @@
#include <asm/debugfs.h>
#include <asm/security_features.h>
#include <asm/setup.h>
+#include <asm/inst.h>
-unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
+u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
-enum count_cache_flush_type {
- COUNT_CACHE_FLUSH_NONE = 0x1,
- COUNT_CACHE_FLUSH_SW = 0x2,
- COUNT_CACHE_FLUSH_HW = 0x4,
+enum branch_cache_flush_type {
+ BRANCH_CACHE_FLUSH_NONE = 0x1,
+ BRANCH_CACHE_FLUSH_SW = 0x2,
+ BRANCH_CACHE_FLUSH_HW = 0x4,
};
-static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
-static bool link_stack_flush_enabled;
+static enum branch_cache_flush_type count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
+static enum branch_cache_flush_type link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
bool barrier_nospec_enabled;
static bool no_nospec;
@@ -95,16 +98,25 @@
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
- barrier_nospec_get, barrier_nospec_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_barrier_nospec, barrier_nospec_get,
+ barrier_nospec_set, "%llu\n");
static __init int barrier_nospec_debugfs_init(void)
{
- debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
- &fops_barrier_nospec);
+ debugfs_create_file_unsafe("barrier_nospec", 0600,
+ powerpc_debugfs_root, NULL,
+ &fops_barrier_nospec);
return 0;
}
device_initcall(barrier_nospec_debugfs_init);
+
+static __init int security_feature_debugfs_init(void)
+{
+ debugfs_create_x64("security_features", 0400, powerpc_debugfs_root,
+ &powerpc_security_features);
+ return 0;
+}
+device_initcall(security_feature_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_BOOK3S_64)
@@ -207,22 +219,23 @@
if (ccd)
seq_buf_printf(&s, "Indirect branch cache disabled");
- if (link_stack_flush_enabled)
- seq_buf_printf(&s, ", Software link stack flush");
-
- } else if (count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
+ } else if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
seq_buf_printf(&s, "Mitigation: Software count cache flush");
- if (count_cache_flush_type == COUNT_CACHE_FLUSH_HW)
+ if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW)
seq_buf_printf(&s, " (hardware accelerated)");
-
- if (link_stack_flush_enabled)
- seq_buf_printf(&s, ", Software link stack flush");
} else if (btb_flush_enabled) {
seq_buf_printf(&s, "Mitigation: Branch predictor state flush");
} else {
seq_buf_printf(&s, "Vulnerable");
+ }
+
+ if (bcs || ccd || count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
+ if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
+ seq_buf_printf(&s, ", Software link stack flush");
+ if (link_stack_flush_type == BRANCH_CACHE_FLUSH_HW)
+ seq_buf_printf(&s, " (hardware accelerated)");
}
seq_buf_printf(&s, "\n");
@@ -349,6 +362,40 @@
return sprintf(buf, "Vulnerable\n");
}
+static int ssb_prctl_get(struct task_struct *task)
+{
+ if (stf_enabled_flush_types == STF_BARRIER_NONE)
+ /*
+ * We don't have an explicit signal from firmware that we're
+ * vulnerable or not, we only have certain CPU revisions that
+ * are known to be vulnerable.
+ *
+ * We assume that if we're on another CPU, where the barrier is
+ * NONE, then we are not vulnerable.
+ */
+ return PR_SPEC_NOT_AFFECTED;
+ else
+ /*
+ * If we do have a barrier type then we are vulnerable. The
+ * barrier is not a global or per-process mitigation, so the
+ * only value we can report here is PR_SPEC_ENABLE, which
+ * appears as "vulnerable" in /proc.
+ */
+ return PR_SPEC_ENABLE;
+
+ return -EINVAL;
+}
+
+int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
+{
+ switch (which) {
+ case PR_SPEC_STORE_BYPASS:
+ return ssb_prctl_get(task);
+ default:
+ return -ENODEV;
+ }
+}
+
#ifdef CONFIG_DEBUG_FS
static int stf_barrier_set(void *data, u64 val)
{
@@ -374,68 +421,105 @@
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set,
+ "%llu\n");
static __init int stf_barrier_debugfs_init(void)
{
- debugfs_create_file("stf_barrier", 0600, powerpc_debugfs_root, NULL, &fops_stf_barrier);
+ debugfs_create_file_unsafe("stf_barrier", 0600, powerpc_debugfs_root,
+ NULL, &fops_stf_barrier);
return 0;
}
device_initcall(stf_barrier_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
-static void no_count_cache_flush(void)
+static void update_branch_cache_flush(void)
{
- count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
- pr_info("count-cache-flush: software flush disabled.\n");
+ u32 *site;
+
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+ site = &patch__call_kvm_flush_link_stack;
+ // This controls the branch from guest_exit_cont to kvm_flush_link_stack
+ if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+ patch_instruction_site(site, ppc_inst(PPC_INST_NOP));
+ } else {
+ // Could use HW flush, but that could also flush count cache
+ patch_branch_site(site, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
+ }
+#endif
+
+ // Patch out the bcctr first, then nop the rest
+ site = &patch__call_flush_branch_caches3;
+ patch_instruction_site(site, ppc_inst(PPC_INST_NOP));
+ site = &patch__call_flush_branch_caches2;
+ patch_instruction_site(site, ppc_inst(PPC_INST_NOP));
+ site = &patch__call_flush_branch_caches1;
+ patch_instruction_site(site, ppc_inst(PPC_INST_NOP));
+
+ // This controls the branch from _switch to flush_branch_caches
+ if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE &&
+ link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+ // Nothing to be done
+
+ } else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW &&
+ link_stack_flush_type == BRANCH_CACHE_FLUSH_HW) {
+ // Patch in the bcctr last
+ site = &patch__call_flush_branch_caches1;
+ patch_instruction_site(site, ppc_inst(0x39207fff)); // li r9,0x7fff
+ site = &patch__call_flush_branch_caches2;
+ patch_instruction_site(site, ppc_inst(0x7d2903a6)); // mtctr r9
+ site = &patch__call_flush_branch_caches3;
+ patch_instruction_site(site, ppc_inst(PPC_INST_BCCTR_FLUSH));
+
+ } else {
+ patch_branch_site(site, (u64)&flush_branch_caches, BRANCH_SET_LINK);
+
+ // If we just need to flush the link stack, early return
+ if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE) {
+ patch_instruction_site(&patch__flush_link_stack_return,
+ ppc_inst(PPC_INST_BLR));
+
+ // If we have flush instruction, early return
+ } else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW) {
+ patch_instruction_site(&patch__flush_count_cache_return,
+ ppc_inst(PPC_INST_BLR));
+ }
+ }
}
-static void toggle_count_cache_flush(bool enable)
+static void toggle_branch_cache_flush(bool enable)
{
- if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE) &&
- !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK))
- enable = false;
+ if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
+ if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE)
+ count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
- if (!enable) {
- patch_instruction_site(&patch__call_flush_count_cache, PPC_INST_NOP);
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- patch_instruction_site(&patch__call_kvm_flush_link_stack, PPC_INST_NOP);
-#endif
- pr_info("link-stack-flush: software flush disabled.\n");
- link_stack_flush_enabled = false;
- no_count_cache_flush();
- return;
+ pr_info("count-cache-flush: flush disabled.\n");
+ } else {
+ if (security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
+ count_cache_flush_type = BRANCH_CACHE_FLUSH_HW;
+ pr_info("count-cache-flush: hardware flush enabled.\n");
+ } else {
+ count_cache_flush_type = BRANCH_CACHE_FLUSH_SW;
+ pr_info("count-cache-flush: software flush enabled.\n");
+ }
}
- // This enables the branch from _switch to flush_count_cache
- patch_branch_site(&patch__call_flush_count_cache,
- (u64)&flush_count_cache, BRANCH_SET_LINK);
+ if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK)) {
+ if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
+ link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;
-#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
- // This enables the branch from guest_exit_cont to kvm_flush_link_stack
- patch_branch_site(&patch__call_kvm_flush_link_stack,
- (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
-#endif
-
- pr_info("link-stack-flush: software flush enabled.\n");
- link_stack_flush_enabled = true;
-
- // If we just need to flush the link stack, patch an early return
- if (!security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
- patch_instruction_site(&patch__flush_link_stack_return, PPC_INST_BLR);
- no_count_cache_flush();
- return;
+ pr_info("link-stack-flush: flush disabled.\n");
+ } else {
+ if (security_ftr_enabled(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST)) {
+ link_stack_flush_type = BRANCH_CACHE_FLUSH_HW;
+ pr_info("link-stack-flush: hardware flush enabled.\n");
+ } else {
+ link_stack_flush_type = BRANCH_CACHE_FLUSH_SW;
+ pr_info("link-stack-flush: software flush enabled.\n");
+ }
}
- if (!security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
- count_cache_flush_type = COUNT_CACHE_FLUSH_SW;
- pr_info("count-cache-flush: full software flush sequence enabled.\n");
- return;
- }
-
- patch_instruction_site(&patch__flush_count_cache_return, PPC_INST_BLR);
- count_cache_flush_type = COUNT_CACHE_FLUSH_HW;
- pr_info("count-cache-flush: hardware assisted flush sequence enabled\n");
+ update_branch_cache_flush();
}
void setup_count_cache_flush(void)
@@ -459,7 +543,7 @@
security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE))
security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);
- toggle_count_cache_flush(enable);
+ toggle_branch_cache_flush(enable);
}
#ifdef CONFIG_DEBUG_FS
@@ -474,14 +558,14 @@
else
return -EINVAL;
- toggle_count_cache_flush(enable);
+ toggle_branch_cache_flush(enable);
return 0;
}
static int count_cache_flush_get(void *data, u64 *val)
{
- if (count_cache_flush_type == COUNT_CACHE_FLUSH_NONE)
+ if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE)
*val = 0;
else
*val = 1;
@@ -489,13 +573,14 @@
return 0;
}
-DEFINE_SIMPLE_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
- count_cache_flush_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
+ count_cache_flush_set, "%llu\n");
static __init int count_cache_flush_debugfs_init(void)
{
- debugfs_create_file("count_cache_flush", 0600, powerpc_debugfs_root,
- NULL, &fops_count_cache_flush);
+ debugfs_create_file_unsafe("count_cache_flush", 0600,
+ powerpc_debugfs_root, NULL,
+ &fops_count_cache_flush);
return 0;
}
device_initcall(count_cache_flush_debugfs_init);
--
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