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target/ppc: Disconnect hflags from MSR

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Copying flags directly from msr has drawbacks: (1) msr bits
mean different things per cpu, (2) msr has 64 bits on 64 cpus
while tb->flags has only 32 bits.

Create a enum to define these bits.  Document the origin of each bit
and validate those bits that must match MSR.  This fixes the
truncation of env->hflags to tb->flags, because we no longer
have hflags bits set above bit 31.

Most of the code in ppc_tr_init_disas_context is moved over to
hreg_compute_hflags.  Some of it is simple extractions from msr,
some requires examining other cpu flags.  Anything that is moved
becomes a simple extract from hflags in ppc_tr_init_disas_context.

Several existing bugs are left in ppc_tr_init_disas_context, where
additional changes are required -- to be addressed in future patches.

Remove a broken #if 0 block.

Reported-by: Ivan Warren <ivan@vmfacility.fr>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210323184340.619757-3-richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Richard Henderson 2021-03-23 12:43:32 -06:00 • committed by David Gibson
parent edece45d4a
commit 2df4fe7abe
3 changed files with 95 additions and 50 deletions
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25
target/ppc/cpu.h
View file

@ -585,6 +585,31 @@ enum {
POWERPC_FLAG_HID0_LE = 0x00400000,
};
/*
* Bits for env->hflags.
*
* Most of these bits overlap with corresponding bits in MSR,
* but some come from other sources. Those that do come from
* the MSR are validated in hreg_compute_hflags.
*/
enum {
HFLAGS_LE = 0, /* MSR_LE -- comes from elsewhere on 601 */
HFLAGS_HV = 1, /* computed from MSR_HV and other state */
HFLAGS_64 = 2, /* computed from MSR_CE and MSR_SF */
HFLAGS_DR = 4, /* MSR_DR */
HFLAGS_IR = 5, /* MSR_IR */
HFLAGS_SPE = 6, /* from MSR_SPE if cpu has SPE; avoid overlap w/ MSR_VR */
HFLAGS_VSX = 7, /* from MSR_VSX if cpu has VSX; avoid overlap w/ MSR_AP */
HFLAGS_TM = 8, /* computed from MSR_TM */
HFLAGS_BE = 9, /* MSR_BE -- from elsewhere on embedded ppc */
HFLAGS_SE = 10, /* MSR_SE -- from elsewhere on embedded ppc */
HFLAGS_FP = 13, /* MSR_FP */
HFLAGS_PR = 14, /* MSR_PR */
HFLAGS_SA = 22, /* MSR_SA */
HFLAGS_AP = 23, /* MSR_AP */
HFLAGS_VR = 25, /* MSR_VR if cpu has VRE */
};
/*****************************************************************************/
/* Floating point status and control register */
#define FPSCR_DRN2 34 /* Decimal Floating-Point rounding control */