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target/ppc: Streamline calculation of RMA limit from LPCR[RMLS] 

Currently we use a big switch statement in ppc_hash64_update_rmls() to work
out what the right RMA limit is based on the LPCR[RMLS] field.  There's no
formula for this - it's just an arbitrary mapping defined by the existing
CPU implementations - but we can make it a bit more readable by using a
lookup table rather than a switch.  In addition we can use the MiB/GiB
symbols to make it a bit clearer.

While there we add a bit of clarity and rationale to the comment about
what happens if the LPCR[RMLS] doesn't contain a valid value.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
This commit is contained in:
David Gibson 2020-01-06 16:52:26 +11:00
parent e232eccc75
commit a864a6b382
1 changed files with 27 additions and 36 deletions
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63
target/ppc/mmu-hash64.c
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@ -18,6 +18,7 @@
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
@ -757,6 +758,31 @@ static void ppc_hash64_set_c(PowerPCCPU *cpu, hwaddr ptex, uint64_t pte1)
stb_phys(CPU(cpu)->as, base + offset, (pte1 & 0xff) | 0x80);
}
static target_ulong rmls_limit(PowerPCCPU *cpu)
{
CPUPPCState *env = &cpu->env;
/*
* This is the full 4 bits encoding of POWER8. Previous
* CPUs only support a subset of these but the filtering
* is done when writing LPCR.
*
* Unsupported values mean the OS has shot itself in the
* foot. Return a 0-sized RMA in this case, which we expect
* to trigger an immediate DSI or ISI
*/
static const target_ulong rma_sizes[16] = {
[1] = 16 * GiB,
[2] = 1 * GiB,
[3] = 64 * MiB,
[4] = 256 * MiB,
[7] = 128 * MiB,
[8] = 32 * MiB,
};
target_ulong rmls = (env->spr[SPR_LPCR] & LPCR_RMLS) >> LPCR_RMLS_SHIFT;
return rma_sizes[rmls];
}
int ppc_hash64_handle_mmu_fault(PowerPCCPU *cpu, vaddr eaddr,
int rwx, int mmu_idx)
{
@ -1006,41 +1032,6 @@ void ppc_hash64_tlb_flush_hpte(PowerPCCPU *cpu, target_ulong ptex,
cpu->env.tlb_need_flush = TLB_NEED_GLOBAL_FLUSH | TLB_NEED_LOCAL_FLUSH;
}
static void ppc_hash64_update_rmls(PowerPCCPU *cpu)
{
CPUPPCState *env = &cpu->env;
uint64_t lpcr = env->spr[SPR_LPCR];
/*
* This is the full 4 bits encoding of POWER8. Previous
* CPUs only support a subset of these but the filtering
* is done when writing LPCR
*/
switch ((lpcr & LPCR_RMLS) >> LPCR_RMLS_SHIFT) {
case 0x8: /* 32MB */
env->rmls = 0x2000000ull;
break;
case 0x3: /* 64MB */
env->rmls = 0x4000000ull;
break;
case 0x7: /* 128MB */
env->rmls = 0x8000000ull;
break;
case 0x4: /* 256MB */
env->rmls = 0x10000000ull;
break;
case 0x2: /* 1GB */
env->rmls = 0x40000000ull;
break;
case 0x1: /* 16GB */
env->rmls = 0x400000000ull;
break;
default:
/* What to do here ??? */
env->rmls = 0;
}
}
static void ppc_hash64_update_vrma(PowerPCCPU *cpu)
{
CPUPPCState *env = &cpu->env;
@ -1099,7 +1090,7 @@ void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val)
CPUPPCState *env = &cpu->env;
env->spr[SPR_LPCR] = val & pcc->lpcr_mask;
ppc_hash64_update_rmls(cpu);
env->rmls = rmls_limit(cpu);
ppc_hash64_update_vrma(cpu);
}