powerpc/align: Convert emulate_spe() to scoped user access

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

Convert emulate_spe() 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/4ff83cb240da4e2d0c34e2bce4b8b6ef19a33777.1773136880.git.chleroy@kernel.org

diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c
index 3e37ece067391ee99db866ff97c125915e04f9ba..61409431138f4aa80ff968240e9ba73963d83a1a 100644 (file)
--- a/arch/powerpc/kernel/align.c
+++ b/arch/powerpc/kernel/align.c
@@ -165,25 +165,23 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
                temp.ll = data.ll = 0;
                p = addr;
 
-               if (!user_read_access_begin(addr, nb))
-                       return -EFAULT;
-
-               switch (nb) {
-               case 8:
-                       unsafe_get_user(temp.v[0], p++, Efault_read);
-                       unsafe_get_user(temp.v[1], p++, Efault_read);
-                       unsafe_get_user(temp.v[2], p++, Efault_read);
-                       unsafe_get_user(temp.v[3], p++, Efault_read);
-                       fallthrough;
-               case 4:
-                       unsafe_get_user(temp.v[4], p++, Efault_read);
-                       unsafe_get_user(temp.v[5], p++, Efault_read);
-                       fallthrough;
-               case 2:
-                       unsafe_get_user(temp.v[6], p++, Efault_read);
-                       unsafe_get_user(temp.v[7], p++, Efault_read);
+               scoped_user_read_access_size(addr, nb, efault) {
+                       switch (nb) {
+                       case 8:
+                               unsafe_get_user(temp.v[0], p++, efault);
+                               unsafe_get_user(temp.v[1], p++, efault);
+                               unsafe_get_user(temp.v[2], p++, efault);
+                               unsafe_get_user(temp.v[3], p++, efault);
+                               fallthrough;
+                       case 4:
+                               unsafe_get_user(temp.v[4], p++, efault);
+                               unsafe_get_user(temp.v[5], p++, efault);
+                               fallthrough;
+                       case 2:
+                               unsafe_get_user(temp.v[6], p++, efault);
+                               unsafe_get_user(temp.v[7], p++, efault);
+                       }
                }
-               user_read_access_end();
 
                switch (instr) {
                case EVLDD:
@@ -252,25 +250,23 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
        if (flags & ST) {
                p = addr;
 
-               if (!user_write_access_begin(addr, nb))
-                       return -EFAULT;
-
-               switch (nb) {
-               case 8:
-                       unsafe_put_user(data.v[0], p++, Efault_write);
-                       unsafe_put_user(data.v[1], p++, Efault_write);
-                       unsafe_put_user(data.v[2], p++, Efault_write);
-                       unsafe_put_user(data.v[3], p++, Efault_write);
-                       fallthrough;
-               case 4:
-                       unsafe_put_user(data.v[4], p++, Efault_write);
-                       unsafe_put_user(data.v[5], p++, Efault_write);
-                       fallthrough;
-               case 2:
-                       unsafe_put_user(data.v[6], p++, Efault_write);
-                       unsafe_put_user(data.v[7], p++, Efault_write);
+               scoped_user_write_access_size(addr, nb, efault) {
+                       switch (nb) {
+                       case 8:
+                               unsafe_put_user(data.v[0], p++, efault);
+                               unsafe_put_user(data.v[1], p++, efault);
+                               unsafe_put_user(data.v[2], p++, efault);
+                               unsafe_put_user(data.v[3], p++, efault);
+                               fallthrough;
+                       case 4:
+                               unsafe_put_user(data.v[4], p++, efault);
+                               unsafe_put_user(data.v[5], p++, efault);
+                               fallthrough;
+                       case 2:
+                               unsafe_put_user(data.v[6], p++, efault);
+                               unsafe_put_user(data.v[7], p++, efault);
+                       }
                }
-               user_write_access_end();
        } else {
                *evr = data.w[0];
                regs->gpr[reg] = data.w[1];
@@ -278,12 +274,7 @@ static int emulate_spe(struct pt_regs *regs, unsigned int reg,
 
        return 1;
 
-Efault_read:
-       user_read_access_end();
-       return -EFAULT;
-
-Efault_write:
-       user_write_access_end();
+efault:
        return -EFAULT;
 }
 #endif /* CONFIG_SPE */