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ppc: Improve emulation of THRM registers

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The 75x and 74xx processors have some thermal monitoring SPRs that
some OSes such as MacOS do use. Our current "dumb" implementation
isn't good enough and will cause some versions of MacOS to hang during
boot.

This lifts an improved emulation from MacOnLinux and adapts it to
qemu, thus fixing the problem.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[dwg: Fixed typo in comment, a number of minor checkpatch warnings,
 and a compile failure with CONFIG_USER_ONLY]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Benjamin Herrenschmidt 2016-06-20 11:27:14 +10:00 committed by David Gibson
parent 820724d170
commit f0278900d3
3 changed files with 54 additions and 3 deletions
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1
target-ppc/helper.h
View file

@ -670,3 +670,4 @@ DEF_HELPER_4(dscli, void, env, fprp, fprp, i32)
DEF_HELPER_4(dscliq, void, env, fprp, fprp, i32)
DEF_HELPER_1(tbegin, void, env)
DEF_HELPER_1(fixup_thrm, void, env)

41
target-ppc/misc_helper.c
View file

@ -166,3 +166,44 @@ void ppc_store_msr(CPUPPCState *env, target_ulong value)
{
hreg_store_msr(env, value, 0);
}
/* This code is lifted from MacOnLinux. It is called whenever
* THRM1,2 or 3 is read an fixes up the values in such a way
* that will make MacOS not hang. These registers exist on some
* 75x and 74xx processors.
*/
void helper_fixup_thrm(CPUPPCState *env)
{
target_ulong v, t;
int i;
#define THRM1_TIN (1 << 31)
#define THRM1_TIV (1 << 30)
#define THRM1_THRES(x) (((x) & 0x7f) << 23)
#define THRM1_TID (1 << 2)
#define THRM1_TIE (1 << 1)
#define THRM1_V (1 << 0)
#define THRM3_E (1 << 0)
if (!(env->spr[SPR_THRM3] & THRM3_E)) {
return;
}
/* Note: Thermal interrupts are unimplemented */
for (i = SPR_THRM1; i <= SPR_THRM2; i++) {
v = env->spr[i];
if (!(v & THRM1_V)) {
continue;
}
v |= THRM1_TIV;
v &= ~THRM1_TIN;
t = v & THRM1_THRES(127);
if ((v & THRM1_TID) && t < THRM1_THRES(24)) {
v |= THRM1_TIN;
}
if (!(v & THRM1_TID) && t > THRM1_THRES(24)) {
v |= THRM1_TIN;
}
env->spr[i] = v;
}
}

15
target-ppc/translate_init.c
View file

@ -1179,23 +1179,32 @@ static void gen_spr_amr(CPUPPCState *env, bool has_iamr)
}
#endif /* TARGET_PPC64 */
#ifndef CONFIG_USER_ONLY
static void spr_read_thrm(DisasContext *ctx, int gprn, int sprn)
{
gen_helper_fixup_thrm(cpu_env);
gen_load_spr(cpu_gpr[gprn], sprn);
spr_load_dump_spr(sprn);
}
#endif /* !CONFIG_USER_ONLY */
static void gen_spr_thrm (CPUPPCState *env)
{
/* Thermal management */
/* XXX : not implemented */
spr_register(env, SPR_THRM1, "THRM1",
SPR_NOACCESS, SPR_NOACCESS,
&spr_read_generic, &spr_write_generic,
&spr_read_thrm, &spr_write_generic,
0x00000000);
/* XXX : not implemented */
spr_register(env, SPR_THRM2, "THRM2",
SPR_NOACCESS, SPR_NOACCESS,
&spr_read_generic, &spr_write_generic,
&spr_read_thrm, &spr_write_generic,
0x00000000);
/* XXX : not implemented */
spr_register(env, SPR_THRM3, "THRM3",
SPR_NOACCESS, SPR_NOACCESS,
&spr_read_generic, &spr_write_generic,
&spr_read_thrm, &spr_write_generic,
0x00000000);
}