From b4aea36b7956eeebfc56314ce0944db1441255ce Mon Sep 17 00:00:00 2001 From: Mohan Kumar M Date: Wed, 21 Mar 2007 11:21:32 +0530 Subject: [PATCH] [POWERPC] Avoid hypervisor statistics calculation in real mode kexec invokes plpar_hcall hypervisor call in real mode. plpar_hcall refers to per cpu variables for accounting hypervisor statistics. These variables may not be in the RMO region, so accesses to them in real mode may result in a data storage exception. This fixes this problem by using a new plpar_hcall_raw function which does not update the hypervisor call statistics. Thanks to Anton for suggesting this idea. Signed-off-by: Mohan Kumar M Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/pseries/hvCall.S | 34 +++++++++++++++++++ arch/powerpc/platforms/pseries/lpar.c | 2 +- .../platforms/pseries/plpar_wrappers.h | 16 +++++++++ include/asm-powerpc/hvcall.h | 14 ++++++++ 4 files changed, 65 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S index 5c7e387898..1501b0a9e7 100644 --- a/arch/powerpc/platforms/pseries/hvCall.S +++ b/arch/powerpc/platforms/pseries/hvCall.S @@ -123,6 +123,40 @@ _GLOBAL(plpar_hcall) blr /* return r3 = status */ +/* + * plpar_hcall_raw can be called in real mode. kexec/kdump need some + * hypervisor calls to be executed in real mode. So plpar_hcall_raw + * does not access the per cpu hypervisor call statistics variables, + * since these variables may not be present in the RMO region. + */ +_GLOBAL(plpar_hcall_raw) + HMT_MEDIUM + + mfcr r0 + stw r0,8(r1) + + std r4,STK_PARM(r4)(r1) /* Save ret buffer */ + + mr r4,r5 + mr r5,r6 + mr r6,r7 + mr r7,r8 + mr r8,r9 + mr r9,r10 + + HVSC /* invoke the hypervisor */ + + ld r12,STK_PARM(r4)(r1) + std r4, 0(r12) + std r5, 8(r12) + std r6, 16(r12) + std r7, 24(r12) + + lwz r0,8(r1) + mtcrf 0xff,r0 + + blr /* return r3 = status */ + _GLOBAL(plpar_hcall9) HMT_MEDIUM diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 7496005566..843ee96432 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -378,7 +378,7 @@ static void pSeries_lpar_hptab_clear(void) /* TODO: Use bulk call */ for (i = 0; i < hpte_count; i++) - plpar_pte_remove(0, i, 0, &dummy1, &dummy2); + plpar_pte_remove_raw(0, i, 0, &dummy1, &dummy2); } /* diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h index 3eb7b294d9..2e4d10c9ee 100644 --- a/arch/powerpc/platforms/pseries/plpar_wrappers.h +++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h @@ -78,6 +78,22 @@ static inline long plpar_pte_remove(unsigned long flags, unsigned long ptex, return rc; } +/* plpar_pte_remove_raw can be called in real mode. It calls plpar_hcall_raw */ +static inline long plpar_pte_remove_raw(unsigned long flags, unsigned long ptex, + unsigned long avpn, unsigned long *old_pteh_ret, + unsigned long *old_ptel_ret) +{ + long rc; + unsigned long retbuf[PLPAR_HCALL_BUFSIZE]; + + rc = plpar_hcall_raw(H_REMOVE, retbuf, flags, ptex, avpn); + + *old_pteh_ret = retbuf[0]; + *old_ptel_ret = retbuf[1]; + + return rc; +} + static inline long plpar_pte_read(unsigned long flags, unsigned long ptex, unsigned long *old_pteh_ret, unsigned long *old_ptel_ret) { diff --git a/include/asm-powerpc/hvcall.h b/include/asm-powerpc/hvcall.h index 60977806d2..62efd9d7a4 100644 --- a/include/asm-powerpc/hvcall.h +++ b/include/asm-powerpc/hvcall.h @@ -236,6 +236,20 @@ long plpar_hcall_norets(unsigned long opcode, ...); #define PLPAR_HCALL_BUFSIZE 4 long plpar_hcall(unsigned long opcode, unsigned long *retbuf, ...); +/** + * plpar_hcall_raw: - Make a hypervisor call without calculating hcall stats + * @opcode: The hypervisor call to make. + * @retbuf: Buffer to store up to 4 return arguments in. + * + * This call supports up to 6 arguments and 4 return arguments. Use + * PLPAR_HCALL_BUFSIZE to size the return argument buffer. + * + * Used when phyp interface needs to be called in real mode. Similar to + * plpar_hcall, but plpar_hcall_raw works in real mode and does not + * calculate hypervisor call statistics. + */ +long plpar_hcall_raw(unsigned long opcode, unsigned long *retbuf, ...); + /** * plpar_hcall9: - Make a pseries hypervisor call with up to 9 return arguments * @opcode: The hypervisor call to make. -- 2.39.5