From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: Re: [PATCH 6/8] xen/x86: Avoid overriding initialisers in arrays Date: Wed, 10 Feb 2016 10:11:33 +0000 Message-ID: <56BB0CD5.2030509@citrix.com> References: <1455048108-5045-1-git-send-email-andrew.cooper3@citrix.com> <1455048108-5045-7-git-send-email-andrew.cooper3@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1455048108-5045-7-git-send-email-andrew.cooper3@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper , Xen-devel Cc: George Dunlap , Kevin Tian , Jun Nakajima , Jan Beulich List-Id: xen-devel@lists.xenproject.org On 09/02/16 20:01, Andrew Cooper wrote: > Clang objects to having multiple initialisers when creating an array. > > As this warning is useful for spotting obscure bugs, disabling it is > unhelpful. Instead, fix our two deliberate usecases. > > In the p2m-ept case, pull the array out into a helper function, so the helper > can guarentee to cover the NULL pointer case. > > No functional change. > > Signed-off-by: Andrew Cooper Acked-by: George Dunlap > --- > CC: Jan Beulich > CC: George Dunlap > CC: Jun Nakajima > CC: Kevin Tian > --- > xen/arch/x86/cpu/mtrr/generic.c | 3 +-- > xen/arch/x86/mm/p2m-ept.c | 27 ++++++++++++++++----------- > 2 files changed, 17 insertions(+), 13 deletions(-) > > diff --git a/xen/arch/x86/cpu/mtrr/generic.c b/xen/arch/x86/cpu/mtrr/generic.c > index ea0efe2..8839f8d 100644 > --- a/xen/arch/x86/cpu/mtrr/generic.c > +++ b/xen/arch/x86/cpu/mtrr/generic.c > @@ -91,7 +91,6 @@ static const char *__init mtrr_attrib_to_str(mtrr_type x) > { > static const char __initconst strings[MTRR_NUM_TYPES][16] = > { > - [0 ... MTRR_NUM_TYPES - 1] = "?", > [MTRR_TYPE_UNCACHABLE] = "uncachable", > [MTRR_TYPE_WRCOMB] = "write-combining", > [MTRR_TYPE_WRTHROUGH] = "write-through", > @@ -99,7 +98,7 @@ static const char *__init mtrr_attrib_to_str(mtrr_type x) > [MTRR_TYPE_WRBACK] = "write-back", > }; > > - return x < MTRR_NUM_TYPES ? strings[x] : "?"; > + return x < MTRR_NUM_TYPES ? (strings[x] ?: "?") : "?"; > } > > static unsigned int __initdata last_fixed_start; > diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c > index c094320..c5fe906 100644 > --- a/xen/arch/x86/mm/p2m-ept.c > +++ b/xen/arch/x86/mm/p2m-ept.c > @@ -1201,6 +1201,20 @@ void ept_p2m_uninit(struct p2m_domain *p2m) > free_cpumask_var(ept->invalidate); > } > > +static const char *memory_type_to_str(unsigned int x) > +{ > + static const char memory_types[8][2] = { > + [MTRR_TYPE_UNCACHABLE] = "UC", > + [MTRR_TYPE_WRCOMB] = "WC", > + [MTRR_TYPE_WRTHROUGH] = "WT", > + [MTRR_TYPE_WRPROT] = "WP", > + [MTRR_TYPE_WRBACK] = "WB", > + [MTRR_NUM_TYPES] = "??" > + }; > + > + return x < ARRAY_SIZE(memory_types) ? (memory_types[x] ?: "?") : "?"; > +} > + > static void ept_dump_p2m_table(unsigned char key) > { > struct domain *d; > @@ -1212,15 +1226,6 @@ static void ept_dump_p2m_table(unsigned char key) > unsigned long record_counter = 0; > struct p2m_domain *p2m; > struct ept_data *ept; > - static const char memory_types[8][2] = { > - [0 ... 7] = "?", > - [MTRR_TYPE_UNCACHABLE] = "UC", > - [MTRR_TYPE_WRCOMB] = "WC", > - [MTRR_TYPE_WRTHROUGH] = "WT", > - [MTRR_TYPE_WRPROT] = "WP", > - [MTRR_TYPE_WRBACK] = "WB", > - [MTRR_NUM_TYPES] = "??" > - }; > > for_each_domain(d) > { > @@ -1260,8 +1265,8 @@ static void ept_dump_p2m_table(unsigned char key) > ept_entry->r ? 'r' : ' ', > ept_entry->w ? 'w' : ' ', > ept_entry->x ? 'x' : ' ', > - memory_types[ept_entry->emt][0], > - memory_types[ept_entry->emt][1] > + memory_type_to_str(ept_entry->emt)[0], > + memory_type_to_str(ept_entry->emt)[1] > ?: ept_entry->emt + '0', > c ?: ept_entry->ipat ? '!' : ' '); > >