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Subject[RFC PATCH v1 39/41] powerpc/32s: Create C version of kuap save/restore/check helpers
Date
In preparation of porting PPC32 to C syscall entry/exit,
create C version of kuap_save_and_lock() and kuap_user_restore() and
kuap_kernel_restore() and kuap_check() and kuap_get_and_check()
on book3s/32.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/kup.h | 45 ++++++++++++++++++++++++
1 file changed, 45 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index b97ea60f6fa3..c9d6c28bcd10 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -72,6 +72,51 @@ static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
isync(); /* Context sync required after mtsr() */
}

+static inline void kuap_save_and_lock(struct pt_regs *regs)
+{
+ unsigned long kuap = current->thread.kuap;
+ u32 addr = kuap & 0xf0000000;
+ u32 end = kuap << 28;
+
+ regs->kuap = kuap;
+ if (unlikely(!kuap))
+ return;
+
+ current->thread.kuap = 0;
+ kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* Set Ks */
+}
+
+static inline void kuap_user_restore(struct pt_regs *regs)
+{
+}
+
+static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+{
+ u32 addr = regs->kuap & 0xf0000000;
+ u32 end = regs->kuap << 28;
+
+ current->thread.kuap = regs->kuap;
+
+ if (unlikely(regs->kuap == kuap))
+ return;
+
+ kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */
+}
+
+static inline unsigned long kuap_get_and_check(void)
+{
+ unsigned long kuap = current->thread.kuap;
+
+ WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != 0);
+
+ return kuap;
+}
+
+static inline void kuap_check(void)
+{
+ kuap_get_and_check();
+}
+
static __always_inline void allow_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
--
2.25.0
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