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authorSandipan Das <sandipan@linux.vnet.ibm.com>2017-09-29 11:14:09 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-10-04 11:28:03 +1100
commitdc39c1d68f256990d4bb0033a219e8ca15ba4d7f (patch)
tree9459c42df2f2d8a8df64a4d588ee859c40ce576a
parent924c8feb041c3ef22d46ac2e7468161aad85e979 (diff)
downloadop-kernel-dev-dc39c1d68f256990d4bb0033a219e8ca15ba4d7f.zip
op-kernel-dev-dc39c1d68f256990d4bb0033a219e8ca15ba4d7f.tar.gz
powerpc/lib/sstep: Fix fixed-point arithmetic instructions that set CA32
There are existing fixed-point arithmetic instructions that always set the CA bit of XER to reflect the carry out of bit 0 in 64-bit mode and out of bit 32 in 32-bit mode. In ISA v3.0, these instructions also always set the CA32 bit of XER to reflect the carry out of bit 32. This fixes the emulated behaviour of such instructions when running on a system that is compliant with POWER ISA v3.0. The following instructions are affected: * Add Immediate Carrying (addic) * Add Immediate Carrying and Record (addic.) * Subtract From Immediate Carrying (subfic) * Add Carrying (addc[.]) * Subtract From Carrying (subfc[.]) * Add Extended (adde[.]) * Subtract From Extended (subfe[.]) * Add to Minus One Extended (addme[.]) * Subtract From Minus One Extended (subfme[.]) * Add to Zero Extended (addze[.]) * Subtract From Zero Extended (subfze[.]) Fixes: 0016a4cf5582 ("powerpc: Emulate most Book I instructions in emulate_step()") Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/lib/sstep.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 16814bf..fe19107 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -964,6 +964,16 @@ static nokprobe_inline void set_cr0(const struct pt_regs *regs,
op->ccval |= 0x20000000;
}
+static nokprobe_inline void set_ca32(struct instruction_op *op, bool val)
+{
+ if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+ if (val)
+ op->xerval |= XER_CA32;
+ else
+ op->xerval &= ~XER_CA32;
+ }
+}
+
static nokprobe_inline void add_with_carry(const struct pt_regs *regs,
struct instruction_op *op, int rd,
unsigned long val1, unsigned long val2,
@@ -987,6 +997,9 @@ static nokprobe_inline void add_with_carry(const struct pt_regs *regs,
op->xerval |= XER_CA;
else
op->xerval &= ~XER_CA;
+
+ set_ca32(op, (unsigned int)val < (unsigned int)val1 ||
+ (carry_in && (unsigned int)val == (unsigned int)val1));
}
static nokprobe_inline void do_cmp_signed(const struct pt_regs *regs,
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