Changeset 1f12fab in mainline for kernel/arch/sparc32/src/trap_table.S

Timestamp:

2013-10-07T20:00:34Z (11 years ago)

Author:

Jakub Klama <jakub.klama@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a73ebf0

Parents:

80d9d83

Message:

First attempt to implement preemptive trap handlers
and switch to userspace. Preemptive traps are needed
for at least page faults, as page fault handling code
can trigger window underflow/overflow exceptions.

This commit also introduces userspace window buffer
for saving userspace register windows (just as in
sparc64).

These changes are unfinished and far from working
correctly.

File:

• kernel/arch/sparc32/src/trap_table.S (modified) (3 diffs)

kernel/arch/sparc32/src/trap_table.S

@@ -33 +33 @@
 .global trap_table
 .global reset_trap
+.global preemptible_trap
 .global window_overflow_trap
 .global window_underflow_trap
@@ -116 +117 @@
         rett %l2
 
-#define TRAP(_vector, _handler) \
+preemptible_trap:
+        /* Enable traps */
+        mov %psr, %l0
+        or %l0, (1 << 5), %l0
+        mov %l0, %psr
+
+        /* Check whether previous mode was usermode */
+        and %l0, (1 << 6), %l0
+        cmp %l0, 0
+        bne 1f
+        nop
+
+        /* Set up stack */
+        set kernel_sp, %l4
+        ld [%l4], %sp
+        mov %sp, %fp
+1:      sub %sp, 112, %sp
+
+        /* Save trap data on stack */
+        st %l1, [%fp - 4]
+        st %l2, [%fp - 8]
+        st %l0, [%fp - 12]
+
+        /* Jump to actual subroutine */
+        mov 1, %o0
+        jmp %g1
+        sub %fp, 12, %o1
+
+        /* Return from handler */
+        ld [%fp - 4], %l1
+        ld [%fp - 8], %l2
+        jmp %l1
+        rett %l2
+
+#define STRAP(_vector, _handler) \
         .org trap_table + _vector * TRAP_ENTRY_SIZE; \
         mov %psr, %l0 ; \
         sethi %hi(_handler), %l4 ; \
-        jmp %l4 + %lo(_handler); \
-        mov _vector, %l3 ;
+        jmp %lo(_handler) + %l4 ; \
+        nop
+
+#define TRAP(_vector, _handler) \
+        .org trap_table + _vector * TRAP_ENTRY_SIZE; \
+        sethi %hi(_handler), %g1 ; \
+        b preemptible_trap ; \
+        or %g1, %lo(_handler), %g1 ;
 
 #define INTERRUPT(_vector, _priority) \
@@ -141 +182 @@
         TRAP(0x3, privileged_instruction)
         TRAP(0x4, fp_disabled)
-        TRAP(0x5, window_overflow_trap)
-        TRAP(0x6, window_underflow_trap)
+        STRAP(0x5, window_overflow_trap)
+        STRAP(0x6, window_underflow_trap)
         TRAP(0x7, mem_address_not_aligned)
         TRAP(0x8, fp_exception)