[PATCH 1/2] Add support for stopping spus from xmon
Luke Browning
LukeBrowning at us.ibm.com
Fri Oct 13 13:18:23 EST 2006
linuxppc-dev-bounces+lukebrowning=us.ibm.com at ozlabs.org wrote on
10/12/2006 09:03:08 AM:
> This patch adds support for stopping, and restarting, spus
> from xmon. We use the spu master runcntl bit to stop execution,
> this is apparently the "right" way to control spu execution and
> spufs will be changed in the future to use this bit.
>
> Testing has shown that to restart execution we have to turn the
> master runcntl bit on and also rewrite the spu runcntl bit, even
> if it is already set to 1 (running).
>
> Stopping spus is triggered by the xmon command 'ss' - "spus stop"
> perhaps. Restarting them is triggered via 'sr'. Restart doesn't
> start execution on spus unless they were running prior to being
> stopped by xmon.
>
> Walking the spu->full_list in xmon after a panic, would mean
> corruption of any spu struct would make all the others
> inaccessible. To avoid this, and also to make the next patch
> easier, we cache pointers to all spus during boot.
The spe affinity code drop created an array of spu pointers that
is indexed by spu->number. We have a couple of other fields in
there that are needed for multiple spu scheduling operations.
Maybe, you can use this array. The name of the arry is lspu[]
for logical spus.
>
> We attempt to catch and recover from errors while stopping and
> restarting the spus, but as with most xmon functionality there are
> no guarantees that performing these operations won't crash xmon
> itself.
>
> Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
> ---
>
> arch/powerpc/platforms/cell/spu_base.c | 4
> arch/powerpc/xmon/xmon.c | 142
> ++++++++++++++++++++++++++++++++-
> include/asm-powerpc/xmon.h | 2
> 3 files changed, 146 insertions(+), 2 deletions(-)
>
> Index: to-merge/arch/powerpc/platforms/cell/spu_base.c
> ===================================================================
> --- to-merge.orig/arch/powerpc/platforms/cell/spu_base.c
> +++ to-merge/arch/powerpc/platforms/cell/spu_base.c
> @@ -38,6 +38,7 @@
> #include <asm/spu.h>
> #include <asm/spu_priv1.h>
> #include <asm/mmu_context.h>
> +#include <asm/xmon.h>
>
> #include "interrupt.h"
>
> @@ -914,6 +915,9 @@ static int __init init_spu_base(void)
> break;
> }
> }
> +
> + xmon_register_spus(&spu_full_list);
> +
> return ret;
> }
> module_init(init_spu_base);
> Index: to-merge/arch/powerpc/xmon/xmon.c
> ===================================================================
> --- to-merge.orig/arch/powerpc/xmon/xmon.c
> +++ to-merge/arch/powerpc/xmon/xmon.c
> @@ -35,6 +35,8 @@
> #include <asm/rtas.h>
> #include <asm/sstep.h>
> #include <asm/bug.h>
> +#include <asm/spu.h>
> +#include <asm/spu_priv1.h>
>
> #ifdef CONFIG_PPC64
> #include <asm/hvcall.h>
> @@ -145,6 +147,8 @@ static void xmon_print_symbol(unsigned l
> const char *after);
> static const char *getvecname(unsigned long vec);
>
> +static int do_spu_cmd(void);
> +
> int xmon_no_auto_backtrace;
>
> extern int print_insn_powerpc(unsigned long, unsigned long, int);
> @@ -207,8 +211,12 @@ Commands:\n\
> mi show information about memory allocation\n\
> p call a procedure\n\
> r print registers\n\
> - s single step\n\
> - S print special registers\n\
> + s single step\n"
> +#ifdef CONFIG_PPC_CELL
> +" ss stop execution on all spus\n\
> + sr restore execution on stopped spus\n"
> +#endif
> +" S print special registers\n\
> t print backtrace\n\
> x exit monitor and recover\n\
> X exit monitor and dont recover\n"
> @@ -516,6 +524,7 @@ int xmon(struct pt_regs *excp)
> xmon_save_regs(®s);
> excp = ®s;
> }
> +
> return xmon_core(excp, 0);
> }
> EXPORT_SYMBOL(xmon);
> @@ -808,6 +817,8 @@ cmds(struct pt_regs *excp)
> cacheflush();
> break;
> case 's':
> + if (do_spu_cmd() == 0)
> + break;
> if (do_step(excp))
> return cmd;
> break;
> @@ -2630,3 +2641,130 @@ void __init xmon_setup(void)
> if (xmon_early)
> debugger(NULL);
> }
> +
> +#ifdef CONFIG_PPC_CELL
> +
> +struct spu_info {
> + struct spu *spu;
> + u64 saved_mfc_sr1_RW;
> + u32 saved_spu_runcntl_RW;
> + u8 stopped_ok;
> +};
> +
> +#define XMON_NUM_SPUS 16 /* Enough for current hardware */
> +
> +static struct spu_info spu_info[XMON_NUM_SPUS];
> +
> +void xmon_register_spus(struct list_head *list)
> +{
> + struct spu *spu;
> +
> + list_for_each_entry(spu, list, full_list) {
> + if (spu->number >= XMON_NUM_SPUS) {
> + WARN_ON(1);
> + continue;
> + }
> +
> + spu_info[spu->number].spu = spu;
> + spu_info[spu->number].stopped_ok = 0;
> + }
> +}
> +
> +static void stop_spus(void)
> +{
> + struct spu *spu;
> + int i;
> + u64 tmp;
> +
> + for (i = 0; i < XMON_NUM_SPUS; i++) {
> + if (!spu_info[i].spu)
> + continue;
> +
> + if (setjmp(bus_error_jmp) == 0) {
> + catch_memory_errors = 1;
> + sync();
> +
> + spu = spu_info[i].spu;
> +
> + spu_info[i].saved_spu_runcntl_RW =
> + in_be32(&spu->problem->spu_runcntl_RW);
> +
> + tmp = spu_mfc_sr1_get(spu);
> + spu_info[i].saved_mfc_sr1_RW = tmp;
> +
> + tmp &= ~MFC_STATE1_MASTER_RUN_CONTROL_MASK;
> + spu_mfc_sr1_set(spu, tmp);
> +
> + sync();
> + __delay(200);
> +
> + spu_info[i].stopped_ok = 1;
> + printf("Stopped spu %.2d\n", i);
> + } else {
> + catch_memory_errors = 0;
> + printf("*** Error stopping spu %.2d\n", i);
> + }
> + catch_memory_errors = 0;
> + }
> +}
> +
> +static void restart_spus(void)
> +{
> + struct spu *spu;
> + int i;
> +
> + for (i = 0; i < XMON_NUM_SPUS; i++) {
> + if (!spu_info[i].spu)
> + continue;
> +
> + if (!spu_info[i].stopped_ok) {
> + printf("*** Error, spu %d was not successfully stopped"
> + ", not restarting\n", i);
> + continue;
> + }
> +
> + if (setjmp(bus_error_jmp) == 0) {
> + catch_memory_errors = 1;
> + sync();
> +
> + spu = spu_info[i].spu;
> + spu_mfc_sr1_set(spu, spu_info[i].saved_mfc_sr1_RW);
> + out_be32(&spu->problem->spu_runcntl_RW,
> + spu_info[i].saved_spu_runcntl_RW);
> +
> + sync();
> + __delay(200);
> +
> + printf("Restarted spu %.2d\n", i);
> + } else {
> + catch_memory_errors = 0;
> + printf("*** Error restarting spu %.2d\n", i);
> + }
> + catch_memory_errors = 0;
> + }
> +}
> +
> +static int do_spu_cmd(void)
> +{
> + int cmd;
> +
> + cmd = inchar();
> + switch (cmd) {
> + case 's':
> + stop_spus();
> + break;
> + case 'r':
> + restart_spus();
> + break;
> + default:
> + return -1;
> + }
> +
> + return 0;
> +}
> +#else /* ! CONFIG_PPC_CELL */
> +static int do_spu_cmd(void)
> +{
> + return -1;
> +}
> +#endif
> Index: to-merge/include/asm-powerpc/xmon.h
> ===================================================================
> --- to-merge.orig/include/asm-powerpc/xmon.h
> +++ to-merge/include/asm-powerpc/xmon.h
> @@ -14,8 +14,10 @@
>
> #ifdef CONFIG_XMON
> extern void xmon_setup(void);
> +extern void xmon_register_spus(struct list_head *list);
> #else
> static inline void xmon_setup(void) { };
> +static inline void xmon_register_spus(struct list_head *list) { };
> #endif
>
> #endif /* __KERNEL __ */
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev at ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
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