[PATCH] powerpc64: remove broken/bitrotted HMT support

HMT support is currently broken and needs to be reworked to play nicely
with the SMT scheduler. Remove the bit rotten bits for the time being.

I also updated an incorrect comment, we enter __secondary_hold with the
physical cpu id in r3.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index bb845ee..11f2cd5 100644 (file)
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -139,7 +139,7 @@ _GLOBAL(__secondary_hold)
        ori     r24,r24,MSR_RI
        mtmsrd  r24                     /* RI on */
 
-       /* Grab our linux cpu number */
+       /* Grab our physical cpu number */
        mr      r24,r3
 
        /* Tell the master cpu we're here */
@@ -153,11 +153,7 @@ _GLOBAL(__secondary_hold)
        cmpdi   0,r4,1
        bne     100b
 
-#ifdef CONFIG_HMT
-       SET_REG_IMMEDIATE(r4, .hmt_init)
-       mtctr   r4
-       bctr
-#elif defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
+#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
        LOAD_REG_IMMEDIATE(r4, .pSeries_secondary_smp_init)
        mtctr   r4
        mr      r3,r24
@@ -1808,22 +1804,6 @@ _STATIC(start_here_multiplatform)
        ori     r6,r6,MSR_RI
        mtmsrd  r6                      /* RI on */
 
-#ifdef CONFIG_HMT
-       /* Start up the second thread on cpu 0 */
-       mfspr   r3,SPRN_PVR
-       srwi    r3,r3,16
-       cmpwi   r3,0x34                 /* Pulsar  */
-       beq     90f
-       cmpwi   r3,0x36                 /* Icestar */
-       beq     90f
-       cmpwi   r3,0x37                 /* SStar   */
-       beq     90f
-       b       91f                     /* HMT not supported */
-90:    li      r3,0
-       bl      .hmt_start_secondary
-91:
-#endif
-
        /* The following gets the stack and TOC set up with the regs */
        /* pointing to the real addr of the kernel stack.  This is   */
        /* all done to support the C function call below which sets  */
@@ -1937,77 +1917,8 @@ _STATIC(start_here_common)
 
        bl .start_kernel
 
-_GLOBAL(hmt_init)
-#ifdef CONFIG_HMT
-       LOAD_REG_IMMEDIATE(r5, hmt_thread_data)
-       mfspr   r7,SPRN_PVR
-       srwi    r7,r7,16
-       cmpwi   r7,0x34                 /* Pulsar  */
-       beq     90f
-       cmpwi   r7,0x36                 /* Icestar */
-       beq     91f
-       cmpwi   r7,0x37                 /* SStar   */
-       beq     91f
-       b       101f
-90:    mfspr   r6,SPRN_PIR
-       andi.   r6,r6,0x1f
-       b       92f
-91:    mfspr   r6,SPRN_PIR
-       andi.   r6,r6,0x3ff
-92:    sldi    r4,r24,3
-       stwx    r6,r5,r4
-       bl      .hmt_start_secondary
-       b       101f
-
-__hmt_secondary_hold:
-       LOAD_REG_IMMEDIATE(r5, hmt_thread_data)
-       clrldi  r5,r5,4
-       li      r7,0
-       mfspr   r6,SPRN_PIR
-       mfspr   r8,SPRN_PVR
-       srwi    r8,r8,16
-       cmpwi   r8,0x34
-       bne     93f
-       andi.   r6,r6,0x1f
-       b       103f
-93:    andi.   r6,r6,0x3f
-
-103:   lwzx    r8,r5,r7
-       cmpw    r8,r6
-       beq     104f
-       addi    r7,r7,8
-       b       103b
-
-104:   addi    r7,r7,4
-       lwzx    r9,r5,r7
-       mr      r24,r9
-101:
-#endif
-       mr      r3,r24
-       b       .pSeries_secondary_smp_init
-
-#ifdef CONFIG_HMT
-_GLOBAL(hmt_start_secondary)
-       LOAD_REG_IMMEDIATE(r4,__hmt_secondary_hold)
-       clrldi  r4,r4,4
-       mtspr   SPRN_NIADORM, r4
-       mfspr   r4, SPRN_MSRDORM
-       li      r5, -65
-       and     r4, r4, r5
-       mtspr   SPRN_MSRDORM, r4
-       lis     r4,0xffef
-       ori     r4,r4,0x7403
-       mtspr   SPRN_TSC, r4
-       li      r4,0x1f4
-       mtspr   SPRN_TST, r4
-       mfspr   r4, SPRN_HID0
-       ori     r4, r4, 0x1
-       mtspr   SPRN_HID0, r4
-       mfspr   r4, SPRN_CTRLF
-       oris    r4, r4, 0x40
-       mtspr   SPRN_CTRLT, r4
-       blr
-#endif
+       /* Not reached */
+       BUG_OPCODE
 
 /*
  * We put a few things here that have to be page-aligned.

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index ec7153f..d34fe53 100644 (file)
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -205,14 +205,6 @@ static cell_t __initdata regbuf[1024];
 
 #define MAX_CPU_THREADS 2
 
-/* TO GO */
-#ifdef CONFIG_HMT
-struct {
-       unsigned int pir;
-       unsigned int threadid;
-} hmt_thread_data[NR_CPUS];
-#endif /* CONFIG_HMT */
-
 /*
  * Error results ... some OF calls will return "-1" on error, some
  * will return 0, some will return either. To simplify, here are
@@ -1319,10 +1311,6 @@ static void __init prom_hold_cpus(void)
         */
        *spinloop = 0;
 
-#ifdef CONFIG_HMT
-       for (i = 0; i < NR_CPUS; i++)
-               RELOC(hmt_thread_data)[i].pir = 0xdeadbeef;
-#endif
        /* look for cpus */
        for (node = 0; prom_next_node(&node); ) {
                type[0] = 0;
@@ -1389,32 +1377,6 @@ static void __init prom_hold_cpus(void)
                /* Reserve cpu #s for secondary threads.   They start later. */
                cpuid += cpu_threads;
        }
-#ifdef CONFIG_HMT
-       /* Only enable HMT on processors that provide support. */
-       if (__is_processor(PV_PULSAR) || 
-           __is_processor(PV_ICESTAR) ||
-           __is_processor(PV_SSTAR)) {
-               prom_printf("    starting secondary threads\n");
-
-               for (i = 0; i < NR_CPUS; i += 2) {
-                       if (!cpu_online(i))
-                               continue;
-
-                       if (i == 0) {
-                               unsigned long pir = mfspr(SPRN_PIR);
-                               if (__is_processor(PV_PULSAR)) {
-                                       RELOC(hmt_thread_data)[i].pir = 
-                                               pir & 0x1f;
-                               } else {
-                                       RELOC(hmt_thread_data)[i].pir = 
-                                               pir & 0x3ff;
-                               }
-                       }
-               }
-       } else {
-               prom_printf("Processor is not HMT capable\n");
-       }
-#endif
 
        if (cpuid > NR_CPUS)
                prom_printf("WARNING: maximum CPUs (" __stringify(NR_CPUS)

diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index e3fc340..4e5c8f8 100644 (file)
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -9,13 +9,6 @@ config PPC_SPLPAR
          processors, that is, which share physical processors between
          two or more partitions.
 
-config HMT
-       bool "Hardware multithreading"
-       depends on SMP && PPC_PSERIES && BROKEN
-       help
-         This option enables hardware multithreading on RS64 cpus.
-         pSeries systems p620 and p660 have such a cpu type.
-
 config EEH
        bool "PCI Extended Error Handling (EEH)" if EMBEDDED
        depends on PPC_PSERIES