MIPS: Use unchecked immediate addition/subtraction

In MIPS assembly there have historically been 2 variants of immediate
addition - the standard "addi" which traps if an overflow occurs, and
the unchecked "addiu" which does not trap on overflow. In release 6 of
the MIPS architecture the trapping variants of immediate addition &
subtraction have been removed. In preparation for supporting MIPSr6,
stop using the trapping instructions from assembly & switch to their
unchecked variants.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S
index 1b56ca350a1cf0cb7bd3a1743ca6fb7125e0d76b..fc6dd66aa655b9e1c7a8b25c5311e96e0ff6f4cb 100644 (file)
--- a/arch/mips/cpu/start.S
+++ b/arch/mips/cpu/start.S
@@ -164,12 +164,14 @@ reset:
        li      t0, -16
        PTR_LI  t1, CONFIG_SYS_INIT_SP_ADDR
        and     sp, t1, t0              # force 16 byte alignment
-       PTR_SUB sp, sp, GD_SIZE         # reserve space for gd
+       PTR_SUBU \
+               sp, sp, GD_SIZE         # reserve space for gd
        and     sp, sp, t0              # force 16 byte alignment
        move    k0, sp                  # save gd pointer
 #ifdef CONFIG_SYS_MALLOC_F_LEN
        li      t2, CONFIG_SYS_MALLOC_F_LEN
-       PTR_SUB sp, sp, t2              # reserve space for early malloc
+       PTR_SUBU \
+               sp, sp, t2              # reserve space for early malloc
        and     sp, sp, t0              # force 16 byte alignment
 #endif
        move    fp, sp
@@ -179,7 +181,7 @@ reset:
 1:
        PTR_S   zero, 0(t0)
        blt     t0, t1, 1b
-        PTR_ADDI t0, PTRSIZE
+        PTR_ADDIU t0, PTRSIZE
 
 #ifdef CONFIG_SYS_MALLOC_F_LEN
        PTR_S   sp, GD_MALLOC_BASE(k0)  # gd->malloc_base offset
@@ -237,7 +239,7 @@ ENTRY(relocate_code)
         move   a0, s2                  # a0 <-- destination address
 
        /* Jump to where we've relocated ourselves */
-       PTR_ADDI t0, s2, in_ram - _start
+       PTR_ADDIU t0, s2, in_ram - _start
        jr      t0
         nop
 
@@ -257,7 +259,7 @@ in_ram:
        PTR_L   t3, -(1 * PTRSIZE)(t0)  # t3 <-- num_got_entries
        PTR_L   t8, -(2 * PTRSIZE)(t0)  # t8 <-- _GLOBAL_OFFSET_TABLE_
        PTR_ADD t8, s1                  # t8 now holds relocated _G_O_T_
-       PTR_ADDI t8, t8, 2 * PTRSIZE    # skipping first two entries
+       PTR_ADDIU t8, t8, 2 * PTRSIZE   # skipping first two entries
        PTR_LI  t2, 2
 1:
        PTR_L   t1, 0(t8)
@@ -265,16 +267,16 @@ in_ram:
         PTR_ADD t1, s1
        PTR_S   t1, 0(t8)
 2:
-       PTR_ADDI t2, 1
+       PTR_ADDIU t2, 1
        blt     t2, t3, 1b
-        PTR_ADDI t8, PTRSIZE
+        PTR_ADDIU t8, PTRSIZE
 
        /* Update dynamic relocations */
        PTR_L   t1, -(4 * PTRSIZE)(t0)  # t1 <-- __rel_dyn_start
        PTR_L   t2, -(5 * PTRSIZE)(t0)  # t2 <-- __rel_dyn_end
 
        b       2f                      # skip first reserved entry
-        PTR_ADDI t1, 2 * PTRSIZE
+        PTR_ADDIU t1, 2 * PTRSIZE
 
 1:
        lw      t8, -4(t1)              # t8 <-- relocation info
@@ -293,7 +295,7 @@ in_ram:
 
 2:
        blt     t1, t2, 1b
-        PTR_ADDI t1, 2 * PTRSIZE       # each rel.dyn entry is 2*PTRSIZE bytes
+        PTR_ADDIU t1, 2 * PTRSIZE      # each rel.dyn entry is 2*PTRSIZE bytes
 
        /*
         * Clear BSS
@@ -307,7 +309,7 @@ in_ram:
 1:
        PTR_S   zero, 0(t1)
        blt     t1, t2, 1b
-        PTR_ADDI t1, PTRSIZE
+        PTR_ADDIU t1, PTRSIZE
 
        move    a0, s0                  # a0 <-- gd
        move    a1, s2

diff --git a/arch/mips/lib/cache_init.S b/arch/mips/lib/cache_init.S
index 14cc2c49fda23c30e7d9fdb2d2f2bf4ad88941ef..08b7c3af5254b80b08e2ecd04a815795e9ca458a 100644 (file)
--- a/arch/mips/lib/cache_init.S
+++ b/arch/mips/lib/cache_init.S
@@ -64,7 +64,7 @@
        /* detect associativity */
        srl     \sz, $1, \off + MIPS_CONF1_DA_SHF - MIPS_CONF1_DA_SHF
        andi    \sz, \sz, (MIPS_CONF1_DA >> MIPS_CONF1_DA_SHF)
-       addi    \sz, \sz, 1
+       addiu   \sz, \sz, 1
 
        /* sz *= line_sz */
        mul     \sz, \sz, \line_sz