On Mon, 21 Mar 2016 12:33:33 +0100
Laurent Vivier <lvivier@xxxxxxxxxx> wrote:
> Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx>
Revieed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> v2:
> use "mtxer" instead of "mtspr"
> Fix comments in lswx asm()
> add "memory" in clobber list
>
> powerpc/emulator.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 140 insertions(+)
>
> diff --git a/powerpc/emulator.c b/powerpc/emulator.c
> index d97090c..8d0dde2 100644
> --- a/powerpc/emulator.c
> +++ b/powerpc/emulator.c
> @@ -56,6 +56,145 @@ static void test_64bit(void)
> report_prefix_pop();
> }
>
> +/*
> + * lswx: Load String Word Indexed X-form
> + *
> + * lswx RT,RA,RB
> + *
> + * EA = (RA|0) + RB
> + * n = XER
> + *
> + * Load n bytes from address EA into (n / 4) consecutive registers,
> + * throught RT -> RT + (n / 4) - 1.
> + * - Data are loaded into 4 low order bytes of registers (Word).
> + * - The unfilled bytes are set to 0.
> + * - The sequence of registers wraps around to GPR0.
> + * - if n == 0, content of RT is undefined
> + * - RT <= RA or RB < RT + (n + 4) is invalid or result is undefined
> + * - RT == RA == 0 is invalid
> + *
> + */
> +
> +static void test_lswx(void)
> +{
> + int i;
> + char addr[128];
> + uint64_t regs[32];
> +
> + report_prefix_push("lswx");
> +
> + /* fill memory with sequence */
> +
> + for (i = 0; i < 128; i++)
> + addr[i] = 1 + i;
> +
> + /* check incomplete register filling */
> +
> + asm volatile ("mtxer %[len];"
> + "li r12,-1;"
> + "mr r11, r12;"
> + "lswx r11, 0, %[addr];"
> + "std r11, 0*8(%[regs]);"
> + "std r12, 1*8(%[regs]);"
> + ::
> + [len] "r" (3),
> + [addr] "r" (addr),
> + [regs] "r" (regs)
> + :
> + "xer", "r11", "r12", "memory");
> +
> + report("partial", regs[0] == 0x01020300 && regs[1] == (uint64_t)-1);
> +
> + /* check an old know bug: the number of bytes is used as
> + * the number of registers, so try 32 bytes.
> + */
> +
> + asm volatile ("mtxer %[len];"
> + "li r19,-1;"
> + "mr r11, r19; mr r12, r19; mr r13, r19;"
> + "mr r14, r19; mr r15, r19; mr r16, r19;"
> + "mr r17, r19; mr r18, r19;"
> + "lswx r11, 0, %[addr];"
> + "std r11, 0*8(%[regs]);"
> + "std r12, 1*8(%[regs]);"
> + "std r13, 2*8(%[regs]);"
> + "std r14, 3*8(%[regs]);"
> + "std r15, 4*8(%[regs]);"
> + "std r16, 5*8(%[regs]);"
> + "std r17, 6*8(%[regs]);"
> + "std r18, 7*8(%[regs]);"
> + "std r19, 8*8(%[regs]);"
> + ::
> + [len] "r" (32),
> + [addr] "r" (addr),
> + [regs] "r" (regs)
> + :
> + /* as 32 is the number of bytes,
> + * we should modify 32/4 = 8 regs, from r11 to r18
> + * We check r19 is unmodified by filling it with 1s
> + * before the instruction.
> + */
> + "xer", "r11", "r12", "r13", "r14", "r15", "r16", "r17",
> + "r18", "r19", "memory");
> +
> + report("length", regs[0] == 0x01020304 && regs[1] == 0x05060708 &&
> + regs[2] == 0x090a0b0c && regs[3] == 0x0d0e0f10 &&
> + regs[4] == 0x11121314 && regs[5] == 0x15161718 &&
> + regs[6] == 0x191a1b1c && regs[7] == 0x1d1e1f20 &&
> + regs[8] == (uint64_t)-1);
> +
> + /* check wrap around to r0 */
> +
> + asm volatile ("mtxer %[len];"
> + "li r31,-1;"
> + "mr r0, r31;"
> + "lswx r31, 0, %[addr];"
> + "std r31, 0*8(%[regs]);"
> + "std r0, 1*8(%[regs]);"
> + ::
> + [len] "r" (8),
> + [addr] "r" (addr),
> + [regs] "r" (regs)
> + :
> + /* modify two registers from r31, wrap around to r0 */
> + "xer", "r31", "r0", "memory");
> +
> + report("wrap around to r0", regs[0] == 0x01020304 &&
> + regs[1] == 0x05060708);
> +
> + /* check wrap around to r0 over RB doesn't break RB */
> +
> + asm volatile ("mtxer %[len];"
> + /* adding r1 in the clobber list doesn't protect it... */
> + "mr r29,r1;"
> + "li r31,-1;"
> + "mr r1,r31;"
> + "mr r0, %[addr];"
> + "lswx r31, 0, r0;"
> + "std r31, 0*8(%[regs]);"
> + "std r0, 1*8(%[regs]);"
> + "std r1, 2*8(%[regs]);"
> + "mr r1,r29;"
> + ::
> + [len] "r" (12),
> + [addr] "r" (addr),
> + [regs] "r" (regs)
> + :
> + /* three registers from r31, wrap arount to r1,
> + * r1 is saved to r29, as adding it to the clobber
> + * list doesn't protect it
> + */
> + "xer", "r31", "r0", "r29", "memory");
> +
> + /* doc says it is invalid, real proc stops when it comes to
> + * overwrite the register.
> + * In all the cases, the register must stay untouched
> + */
> + report("Don't overwrite Rb", regs[1] == (uint64_t)addr);
> +
> + report_prefix_pop();
> +}
> +
> int main(int argc, char **argv)
> {
> int i;
> @@ -72,6 +211,7 @@ int main(int argc, char **argv)
>
> test_64bit();
> test_illegal();
> + test_lswx();
>
> report_prefix_pop();
>
> --
> 2.5.0
>
--
David Gibson <dgibson@xxxxxxxxxx>
Senior Software Engineer, Virtualization, Red Hat
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