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-rw-r--r--arch/powerpc/include/asm/book3s/64/kup-radix.h66
-rw-r--r--arch/powerpc/include/asm/exception-64s.h3
-rw-r--r--arch/powerpc/include/asm/feature-fixups.h9
-rw-r--r--arch/powerpc/include/asm/kup.h19
-rw-r--r--arch/powerpc/include/asm/security_features.h3
-rw-r--r--arch/powerpc/include/asm/setup.h1
6 files changed, 72 insertions, 29 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index 3ee1ec60be84..97c2394e7dea 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -61,6 +61,8 @@
#else /* !__ASSEMBLY__ */
+DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
+
#ifdef CONFIG_PPC_KUAP
#include <asm/mmu.h>
@@ -103,8 +105,16 @@ static inline void kuap_check_amr(void)
static inline unsigned long get_kuap(void)
{
+ /*
+ * We return AMR_KUAP_BLOCKED when we don't support KUAP because
+ * prevent_user_access_return needs to return AMR_KUAP_BLOCKED to
+ * cause restore_user_access to do a flush.
+ *
+ * This has no effect in terms of actually blocking things on hash,
+ * so it doesn't break anything.
+ */
if (!early_mmu_has_feature(MMU_FTR_RADIX_KUAP))
- return 0;
+ return AMR_KUAP_BLOCKED;
return mfspr(SPRN_AMR);
}
@@ -123,6 +133,31 @@ static inline void set_kuap(unsigned long value)
isync();
}
+static inline bool
+bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
+{
+ return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) &&
+ (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)),
+ "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read");
+}
+#else /* CONFIG_PPC_KUAP */
+static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr) { }
+
+static inline unsigned long kuap_get_and_check_amr(void)
+{
+ return 0UL;
+}
+
+static inline void kuap_check_amr(void) { }
+
+static inline unsigned long get_kuap(void)
+{
+ return AMR_KUAP_BLOCKED;
+}
+
+static inline void set_kuap(unsigned long value) { }
+#endif /* !CONFIG_PPC_KUAP */
+
static __always_inline void allow_user_access(void __user *to, const void __user *from,
unsigned long size, unsigned long dir)
{
@@ -142,6 +177,8 @@ static inline void prevent_user_access(void __user *to, const void __user *from,
unsigned long size, unsigned long dir)
{
set_kuap(AMR_KUAP_BLOCKED);
+ if (static_branch_unlikely(&uaccess_flush_key))
+ do_uaccess_flush();
}
static inline unsigned long prevent_user_access_return(void)
@@ -149,6 +186,8 @@ static inline unsigned long prevent_user_access_return(void)
unsigned long flags = get_kuap();
set_kuap(AMR_KUAP_BLOCKED);
+ if (static_branch_unlikely(&uaccess_flush_key))
+ do_uaccess_flush();
return flags;
}
@@ -156,30 +195,9 @@ static inline unsigned long prevent_user_access_return(void)
static inline void restore_user_access(unsigned long flags)
{
set_kuap(flags);
+ if (static_branch_unlikely(&uaccess_flush_key) && flags == AMR_KUAP_BLOCKED)
+ do_uaccess_flush();
}
-
-static inline bool
-bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
-{
- return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) &&
- (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)),
- "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read");
-}
-#else /* CONFIG_PPC_KUAP */
-static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr)
-{
-}
-
-static inline void kuap_check_amr(void)
-{
-}
-
-static inline unsigned long kuap_get_and_check_amr(void)
-{
- return 0;
-}
-#endif /* CONFIG_PPC_KUAP */
-
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H */
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 83fa88bc9935..1d32b174ab6a 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -144,6 +144,9 @@
RFSCV; \
b rfscv_flush_fallback
+#else /* __ASSEMBLY__ */
+/* Prototype for function defined in exceptions-64s.S */
+void do_uaccess_flush(void);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_EXCEPTION_H */
diff --git a/arch/powerpc/include/asm/feature-fixups.h b/arch/powerpc/include/asm/feature-fixups.h
index 06a48219bbf2..fbd406cd6916 100644
--- a/arch/powerpc/include/asm/feature-fixups.h
+++ b/arch/powerpc/include/asm/feature-fixups.h
@@ -205,6 +205,14 @@ label##3: \
FTR_ENTRY_OFFSET 955b-956b; \
.popsection;
+#define UACCESS_FLUSH_FIXUP_SECTION \
+959: \
+ .pushsection __uaccess_flush_fixup,"a"; \
+ .align 2; \
+960: \
+ FTR_ENTRY_OFFSET 959b-960b; \
+ .popsection;
+
#define ENTRY_FLUSH_FIXUP_SECTION \
957: \
.pushsection __entry_flush_fixup,"a"; \
@@ -248,6 +256,7 @@ extern long stf_barrier_fallback;
extern long entry_flush_fallback;
extern long __start___stf_entry_barrier_fixup, __stop___stf_entry_barrier_fixup;
extern long __start___stf_exit_barrier_fixup, __stop___stf_exit_barrier_fixup;
+extern long __start___uaccess_flush_fixup, __stop___uaccess_flush_fixup;
extern long __start___entry_flush_fixup, __stop___entry_flush_fixup;
extern long __start___rfi_flush_fixup, __stop___rfi_flush_fixup;
extern long __start___barrier_nospec_fixup, __stop___barrier_nospec_fixup;
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index 1d0f7d838b2e..0f5c606ae057 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -53,17 +53,26 @@ static inline void setup_kuep(bool disabled) { }
void setup_kuap(bool disabled);
#else
static inline void setup_kuap(bool disabled) { }
+
+static inline bool
+bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
+{
+ return false;
+}
+
+/*
+ * book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
+ * the L1D cache after user accesses. Only include the empty stubs for other
+ * platforms.
+ */
+#ifndef CONFIG_PPC64
static inline void allow_user_access(void __user *to, const void __user *from,
unsigned long size, unsigned long dir) { }
static inline void prevent_user_access(void __user *to, const void __user *from,
unsigned long size, unsigned long dir) { }
static inline unsigned long prevent_user_access_return(void) { return 0UL; }
static inline void restore_user_access(unsigned long flags) { }
-static inline bool
-bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
-{
- return false;
-}
+#endif /* CONFIG_PPC64 */
#endif /* CONFIG_PPC_KUAP */
static inline void allow_read_from_user(const void __user *from, unsigned long size)
diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index 9e7459d2edca..b774a4477d5f 100644
--- a/arch/powerpc/include/asm/security_features.h
+++ b/arch/powerpc/include/asm/security_features.h
@@ -89,6 +89,8 @@ static inline bool security_ftr_enabled(u64 feature)
// The L1-D cache should be flushed when entering the kernel
#define SEC_FTR_L1D_FLUSH_ENTRY 0x0000000000004000ull
+// The L1-D cache should be flushed after user accesses from the kernel
+#define SEC_FTR_L1D_FLUSH_UACCESS 0x0000000000008000ull
// Features enabled by default
#define SEC_FTR_DEFAULT \
@@ -96,6 +98,7 @@ static inline bool security_ftr_enabled(u64 feature)
SEC_FTR_L1D_FLUSH_PR | \
SEC_FTR_BNDS_CHK_SPEC_BAR | \
SEC_FTR_L1D_FLUSH_ENTRY | \
+ SEC_FTR_L1D_FLUSH_UACCESS | \
SEC_FTR_FAVOUR_SECURITY)
#endif /* _ASM_POWERPC_SECURITY_FEATURES_H */
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index e2fcd3e874f8..a466749703f1 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -60,6 +60,7 @@ void setup_barrier_nospec(void);
#else
static inline void setup_barrier_nospec(void) { };
#endif
+void do_uaccess_flush_fixups(enum l1d_flush_type types);
void do_entry_flush_fixups(enum l1d_flush_type types);
void do_barrier_nospec_fixups(bool enable);
extern bool barrier_nospec_enabled;
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-27 03:53:07 +0300