On Mar 25, 2011, at 4:32 PM, Anton Blanchard wrote:
> From: Tseng-Hui (Frank) Lin <th...@linux.vnet.ibm.com>
>
> Icswx is a PowerPC instruction to send data to a co-processor. On Book-S
> processors the LPAR_ID and process ID (PID) of the owning process are
> registered in the window context of the co-processor at initialization
> time. When the icswx instruction is executed the L2 generates a cop-reg
> transaction on PowerBus. The transaction has no address and the
> processor does not perform an MMU access to authenticate the transaction.
> The co-processor compares the LPAR_ID and the PID included in the
> transaction and the LPAR_ID and PID held in the window context to
> determine if the process is authorized to generate the transaction.
>
> The OS needs to assign a 16-bit PID for the process. This cop-PID needs
> to be updated during context switch. The cop-PID needs to be destroyed
> when the context is destroyed.
>
> Signed-off-by: Sonny Rao <sonny...@linux.vnet.ibm.com>
> Signed-off-by: Tseng-Hui (Frank) Lin <th...@linux.vnet.ibm.com>
> Signed-off-by: Anton Blanchard <an...@samba.org>
> ---
>
> This is the v4 patch with a few changes:
>
> - Remove the lazy option. If we see overhead in the context switch path
> we can add it back in once we have the basic patch working and merged.
>
> - Remove comment and ifdef around spinlock forward declaration. We don't
> wrap forward declarations in ifdefs and they are common enough that we
> don't need to explain them individually.
>
> - Check for CPU_FTR_ICSWX in drop_cop. Even though we shouldn't enter with
> mm == active_mm, we export the function and we should avoid doing writes
> to model specific SPRs in any circumstance.
>
> - Convert WARN_ON -> WARN_ON_ONCE in drop_cop.
>
> - Fix comments to be docbook compliant
>
> - Update the Kconfig help text to read a bit better
>
> Index: powerpc.git/arch/powerpc/include/asm/cputable.h
> ===================================================================
> --- powerpc.git.orig/arch/powerpc/include/asm/cputable.h 2011-03-22
> 18:19:30.171445251 +1100
> +++ powerpc.git/arch/powerpc/include/asm/cputable.h 2011-03-26
> 08:15:44.284009603 +1100
> @@ -202,6 +202,7 @@ extern const char *powerpc_base_platform
> #define CPU_FTR_STCX_CHECKS_ADDRESS LONG_ASM_CONST(0x0200000000000000)
> #define CPU_FTR_POPCNTB
> LONG_ASM_CONST(0x0400000000000000)
> #define CPU_FTR_POPCNTD
> LONG_ASM_CONST(0x0800000000000000)
> +#define CPU_FTR_ICSWX
> LONG_ASM_CONST(0x1000000000000000)
>
> #ifndef __ASSEMBLY__
>
> @@ -421,7 +422,8 @@ extern const char *powerpc_base_platform
> CPU_FTR_COHERENT_ICACHE | CPU_FTR_LOCKLESS_TLBIE | \
> CPU_FTR_PURR | CPU_FTR_SPURR | CPU_FTR_REAL_LE | \
> CPU_FTR_DSCR | CPU_FTR_SAO | CPU_FTR_ASYM_SMT | \
> - CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD)
> + CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
> + CPU_FTR_ICSWX)
> #define CPU_FTRS_CELL (CPU_FTR_USE_TB | CPU_FTR_LWSYNC | \
> CPU_FTR_PPCAS_ARCH_V2 | CPU_FTR_CTRL | \
> CPU_FTR_ALTIVEC_COMP | CPU_FTR_MMCRA | CPU_FTR_SMT | \
> Index: powerpc.git/arch/powerpc/include/asm/mmu-hash64.h
> ===================================================================
> --- powerpc.git.orig/arch/powerpc/include/asm/mmu-hash64.h 2011-03-22
> 18:19:30.201446386 +1100
> +++ powerpc.git/arch/powerpc/include/asm/mmu-hash64.h 2011-03-26
> 08:15:44.284009603 +1100
> @@ -408,6 +408,7 @@ static inline void subpage_prot_init_new
> #endif /* CONFIG_PPC_SUBPAGE_PROT */
>
> typedef unsigned long mm_context_id_t;
> +struct spinlock;
>
> typedef struct {
> mm_context_id_t id;
> @@ -423,6 +424,11 @@ typedef struct {
> #ifdef CONFIG_PPC_SUBPAGE_PROT
> struct subpage_prot_table spt;
> #endif /* CONFIG_PPC_SUBPAGE_PROT */
> +#ifdef CONFIG_ICSWX
Seems like this really should be CONFIG_PPC_ICSWX
> + struct spinlock *cop_lockp; /* guard acop and cop_pid */
> + unsigned long acop; /* mask of enabled coprocessor types */
> + unsigned int cop_pid; /* pid value used with coprocessors */
> +#endif /* CONFIG_ICSWX */
> } mm_context_t;
>
>
- k
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