powerpc/sstep: Convert to scoped user access

Commit 861574d51bbd ("powerpc/uaccess: Implement masked user access")
provides optimised user access by avoiding the cost of access_ok().

Convert single step emulation functions to scoped user access to
benefit from masked user access.

Scoped user access also make the code simpler.

Signed-off-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/8f2d85bddacff18046096dc255fd94f6a0f8b230.1773137010.git.chleroy@kernel.org

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ac3ee19531d8acf9f8f16e12be40d23785c8f9fd..f0d6aa657c1acc8d5751221980896b94867dddcf 100644 (file)
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -329,20 +329,17 @@ Efault:
 static nokprobe_inline int
 read_mem_aligned(unsigned long *dest, unsigned long ea, int nb, struct pt_regs *regs)
 {
-       int err;
+       void __user *uea = (void __user *)ea;
 
        if (is_kernel_addr(ea))
                return __read_mem_aligned(dest, ea, nb, regs);
 
-       if (user_read_access_begin((void __user *)ea, nb)) {
-               err = __read_mem_aligned(dest, ea, nb, regs);
-               user_read_access_end();
-       } else {
-               err = -EFAULT;
-               regs->dar = ea;
-       }
+       scoped_user_read_access_size(uea, nb, efault)
+               return __read_mem_aligned(dest, (unsigned long)uea, nb, regs);
 
-       return err;
+efault:
+       regs->dar = ea;
+       return -EFAULT;
 }
 
 /*
@@ -385,20 +382,17 @@ Efault:
 
 static nokprobe_inline int copy_mem_in(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)
 {
-       int err;
+       void __user *uea = (void __user *)ea;
 
        if (is_kernel_addr(ea))
                return __copy_mem_in(dest, ea, nb, regs);
 
-       if (user_read_access_begin((void __user *)ea, nb)) {
-               err = __copy_mem_in(dest, ea, nb, regs);
-               user_read_access_end();
-       } else {
-               err = -EFAULT;
-               regs->dar = ea;
-       }
+       scoped_user_read_access_size(uea, nb, efault)
+               return __copy_mem_in(dest, (unsigned long)uea, nb, regs);
 
-       return err;
+efault:
+       regs->dar = ea;
+       return -EFAULT;
 }
 
 static nokprobe_inline int read_mem_unaligned(unsigned long *dest,
@@ -465,20 +459,17 @@ Efault:
 static nokprobe_inline int
 write_mem_aligned(unsigned long val, unsigned long ea, int nb, struct pt_regs *regs)
 {
-       int err;
+       void __user *uea = (void __user *)ea;
 
        if (is_kernel_addr(ea))
                return __write_mem_aligned(val, ea, nb, regs);
 
-       if (user_write_access_begin((void __user *)ea, nb)) {
-               err = __write_mem_aligned(val, ea, nb, regs);
-               user_write_access_end();
-       } else {
-               err = -EFAULT;
-               regs->dar = ea;
-       }
+       scoped_user_write_access_size(uea, nb, efault)
+               return __write_mem_aligned(val, (unsigned long)uea, nb, regs);
 
-       return err;
+efault:
+       regs->dar = ea;
+       return -EFAULT;
 }
 
 /*
@@ -521,20 +512,17 @@ Efault:
 
 static nokprobe_inline int copy_mem_out(u8 *dest, unsigned long ea, int nb, struct pt_regs *regs)
 {
-       int err;
+       void __user *uea = (void __user *)ea;
 
        if (is_kernel_addr(ea))
                return __copy_mem_out(dest, ea, nb, regs);
 
-       if (user_write_access_begin((void __user *)ea, nb)) {
-               err = __copy_mem_out(dest, ea, nb, regs);
-               user_write_access_end();
-       } else {
-               err = -EFAULT;
-               regs->dar = ea;
-       }
+       scoped_user_write_access_size(uea, nb, efault)
+               return __copy_mem_out(dest, (unsigned long)uea, nb, regs);
 
-       return err;
+efault:
+       regs->dar = ea;
+       return -EFAULT;
 }
 
 static nokprobe_inline int write_mem_unaligned(unsigned long val,
@@ -1065,6 +1053,7 @@ Efault:
 
 int emulate_dcbz(unsigned long ea, struct pt_regs *regs)
 {
+       void __user *uea = (void __user *)ea;
        int err;
        unsigned long size = l1_dcache_bytes();
 
@@ -1073,20 +1062,20 @@ int emulate_dcbz(unsigned long ea, struct pt_regs *regs)
        if (!address_ok(regs, ea, size))
                return -EFAULT;
 
-       if (is_kernel_addr(ea)) {
-               err = __emulate_dcbz(ea);
-       } else if (user_write_access_begin((void __user *)ea, size)) {
+       if (is_kernel_addr(ea))
                err = __emulate_dcbz(ea);
-               user_write_access_end();
-       } else {
-               err = -EFAULT;
-       }
+       else
+               scoped_user_write_access_size(uea, size, efault)
+                       err = __emulate_dcbz((unsigned long)uea);
 
        if (err)
                regs->dar = ea;
 
-
        return err;
+
+efault:
+       regs->dar = ea;
+       return -EFAULT;
 }
 NOKPROBE_SYMBOL(emulate_dcbz);