From 27828f98a0522ad4a745a80407d051e5874c8d93 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 9 Feb 2016 13:32:41 +1000 Subject: [PATCH] powerpc/mm: Handle removing maybe-present bolted HPTEs At the moment the hpte_removebolted callback in ppc_md returns void and will BUG_ON() if the hpte it's asked to remove doesn't exist in the first place. This is awkward for the case of cleaning up a mapping which was partially made before failing. So, we add a return value to hpte_removebolted, and have it return ENOENT in the case that the HPTE to remove didn't exist in the first place. In the (sole) caller, we propagate errors in hpte_removebolted to its caller to handle. However, we handle ENOENT specially, continuing to complete the unmapping over the specified range before returning the error to the caller. This means that htab_remove_mapping() will work sanely on a partially present mapping, removing any HPTEs which are present, while also returning ENOENT to its caller in case it's important there. There are two callers of htab_remove_mapping(): - In remove_section_mapping() we already WARN_ON() any error return, which is reasonable - in this case the mapping should be fully present - In vmemmap_remove_mapping() we BUG_ON() any error. We change that to just a WARN_ON() in the case of ENOENT, since failing to remove a mapping that wasn't there in the first place probably shouldn't be fatal. Signed-off-by: David Gibson Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/machdep.h | 2 +- arch/powerpc/mm/hash_utils_64.c | 15 ++++++++++++--- arch/powerpc/mm/init_64.c | 9 +++++---- arch/powerpc/platforms/pseries/lpar.c | 9 ++++++--- 4 files changed, 24 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h index 5c38e49ddd42..fd22442d30a9 100644 --- a/arch/powerpc/include/asm/machdep.h +++ b/arch/powerpc/include/asm/machdep.h @@ -54,7 +54,7 @@ struct machdep_calls { int psize, int apsize, int ssize); long (*hpte_remove)(unsigned long hpte_group); - void (*hpte_removebolted)(unsigned long ea, + int (*hpte_removebolted)(unsigned long ea, int psize, int ssize); void (*flush_hash_range)(unsigned long number, int local); void (*hugepage_invalidate)(unsigned long vsid, diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 70490c41e14e..44f145a66578 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -269,6 +269,8 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend, { unsigned long vaddr; unsigned int step, shift; + int rc; + int ret = 0; shift = mmu_psize_defs[psize].shift; step = 1 << shift; @@ -276,10 +278,17 @@ int htab_remove_mapping(unsigned long vstart, unsigned long vend, if (!ppc_md.hpte_removebolted) return -ENODEV; - for (vaddr = vstart; vaddr < vend; vaddr += step) - ppc_md.hpte_removebolted(vaddr, psize, ssize); + for (vaddr = vstart; vaddr < vend; vaddr += step) { + rc = ppc_md.hpte_removebolted(vaddr, psize, ssize); + if (rc == -ENOENT) { + ret = -ENOENT; + continue; + } + if (rc < 0) + return rc; + } - return 0; + return ret; } #endif /* CONFIG_MEMORY_HOTPLUG */ diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index 379a6a90644b..baa1a23488d3 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -232,10 +232,11 @@ static void __meminit vmemmap_create_mapping(unsigned long start, static void vmemmap_remove_mapping(unsigned long start, unsigned long page_size) { - int mapped = htab_remove_mapping(start, start + page_size, - mmu_vmemmap_psize, - mmu_kernel_ssize); - BUG_ON(mapped < 0); + int rc = htab_remove_mapping(start, start + page_size, + mmu_vmemmap_psize, + mmu_kernel_ssize); + BUG_ON((rc < 0) && (rc != -ENOENT)); + WARN_ON(rc == -ENOENT); } #endif diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c index 477290ad855e..2415a0d31f8f 100644 --- a/arch/powerpc/platforms/pseries/lpar.c +++ b/arch/powerpc/platforms/pseries/lpar.c @@ -505,8 +505,8 @@ static void pSeries_lpar_hugepage_invalidate(unsigned long vsid, } #endif -static void pSeries_lpar_hpte_removebolted(unsigned long ea, - int psize, int ssize) +static int pSeries_lpar_hpte_removebolted(unsigned long ea, + int psize, int ssize) { unsigned long vpn; unsigned long slot, vsid; @@ -515,11 +515,14 @@ static void pSeries_lpar_hpte_removebolted(unsigned long ea, vpn = hpt_vpn(ea, vsid, ssize); slot = pSeries_lpar_hpte_find(vpn, psize, ssize); - BUG_ON(slot == -1); + if (slot == -1) + return -ENOENT; + /* * lpar doesn't use the passed actual page size */ pSeries_lpar_hpte_invalidate(slot, vpn, psize, 0, ssize, 0); + return 0; } /* -- 2.30.2