sparc64: Add support for ADI (Application Data Integrity)

[linux-2.6-microblaze.git] / arch / sparc / kernel / etrap_64.S

diff --git a/arch/sparc/kernel/etrap_64.S b/arch/sparc/kernel/etrap_64.S
index 5c77a2e..08cc41f 100644 (file)
--- a/arch/sparc/kernel/etrap_64.S
+++ b/arch/sparc/kernel/etrap_64.S
@@ -151,7 +151,32 @@ etrap_save:        save    %g2, -STACK_BIAS, %sp
                stx     %g6, [%sp + PTREGS_OFF + PT_V9_G6]
                stx     %g7, [%sp + PTREGS_OFF + PT_V9_G7]
                or      %l7, %l0, %l7
-               sethi   %hi(TSTATE_TSO | TSTATE_PEF), %l0
+661:           sethi   %hi(TSTATE_TSO | TSTATE_PEF), %l0
+               /* If userspace is using ADI, it could potentially pass
+                * a pointer with version tag embedded in it. To maintain
+                * the ADI security, we must enable PSTATE.mcde. Userspace
+                * would have already set TTE.mcd in an earlier call to
+                * kernel and set the version tag for the address being
+                * dereferenced. Setting PSTATE.mcde would ensure any
+                * access to userspace data through a system call honors
+                * ADI and does not allow a rogue app to bypass ADI by
+                * using system calls. Setting PSTATE.mcde only affects
+                * accesses to virtual addresses that have TTE.mcd set.
+                * Set PMCDPER to ensure any exceptions caused by ADI
+                * version tag mismatch are exposed before system call
+                * returns to userspace. Setting PMCDPER affects only
+                * writes to virtual addresses that have TTE.mcd set and
+                * have a version tag set as well.
+                */
+               .section .sun_m7_1insn_patch, "ax"
+               .word   661b
+               sethi   %hi(TSTATE_TSO | TSTATE_PEF | TSTATE_MCDE), %l0
+               .previous
+661:           nop
+               .section .sun_m7_1insn_patch, "ax"
+               .word   661b
+               .word 0xaf902001        /* wrpr %g0, 1, %pmcdper */
+               .previous
                or      %l7, %l0, %l7
                wrpr    %l2, %tnpc
                wrpr    %l7, (TSTATE_PRIV | TSTATE_IE), %tstate