| Message ID | 20210524172529.3d23c3e7@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: remove page granularity limitation from KFENCE | expand |
On Mon, 24 May 2021 at 11:26, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > Some architectures may want to allocate the __kfence_pool differently > for example, allocate the __kfence_pool earlier before paging_init(). > We also delay the memset() to kfence_init_pool(). > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > --- > mm/kfence/core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index e18fbbd5d9b4..65f0210edb65 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -430,6 +430,8 @@ static bool __init kfence_init_pool(void) > if (!__kfence_pool) > return false; > > + memset(__kfence_pool, 0, KFENCE_POOL_SIZE); > + Use memzero_explicit(). Also, for the arm64 case, is delaying the zeroing relevant? You still call kfence_alloc_pool() in patch 2/2, and zeroing it on memblock_alloc() is not wrong, correct? Essentially if there's not going to be any benefit to us doing the zeroing ourselves, I'd simply leave it as-is and keep using memblock_alloc(). And if there's some odd architecture that doesn't even want to use kfence_alloc_pool(), they could just zero the memory themselves. But we really should use kfence_alloc_pool(), because otherwise it'll just become unmaintainable if on changes to kfence_alloc_pool() we have to go and find other special architectures that don't use it and adjust them, too. Thanks, -- Marco > if (!arch_kfence_init_pool()) > goto err; > > @@ -645,10 +647,10 @@ static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate); > > void __init kfence_alloc_pool(void) > { > - if (!kfence_sample_interval) > + if (!kfence_sample_interval || __kfence_pool) > return; > > - __kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); > + __kfence_pool = memblock_alloc_raw(KFENCE_POOL_SIZE, PAGE_SIZE); > > if (!__kfence_pool) > pr_err("failed to allocate pool\n"); > -- > 2.31.0 >
On Mon, 24 May 2021 12:36:34 +0200 Marco Elver <elver@google.com> wrote: > > > On Mon, 24 May 2021 at 11:26, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > > Some architectures may want to allocate the __kfence_pool differently > > for example, allocate the __kfence_pool earlier before paging_init(). > > We also delay the memset() to kfence_init_pool(). > > > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > > --- > > mm/kfence/core.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > > index e18fbbd5d9b4..65f0210edb65 100644 > > --- a/mm/kfence/core.c > > +++ b/mm/kfence/core.c > > @@ -430,6 +430,8 @@ static bool __init kfence_init_pool(void) > > if (!__kfence_pool) > > return false; > > > > + memset(__kfence_pool, 0, KFENCE_POOL_SIZE); > > + > > Use memzero_explicit(). > > Also, for the arm64 case, is delaying the zeroing relevant? You still > call kfence_alloc_pool() in patch 2/2, and zeroing it on > memblock_alloc() is not wrong, correct? memblock_alloc() returns virtual address which can't be used before paging_init() so I delayed the memset to kfence_init_pool. > > Essentially if there's not going to be any benefit to us doing the > zeroing ourselves, I'd simply leave it as-is and keep using > memblock_alloc(). And if there's some odd architecture that doesn't > even want to use kfence_alloc_pool(), they could just zero the memory > themselves. But we really should use kfence_alloc_pool(), because > otherwise it'll just become unmaintainable if on changes to > kfence_alloc_pool() we have to go and find other special architectures > that don't use it and adjust them, too. > > Thanks, > -- Marco > > > if (!arch_kfence_init_pool()) > > goto err; > > > > @@ -645,10 +647,10 @@ static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate); > > > > void __init kfence_alloc_pool(void) > > { > > - if (!kfence_sample_interval) > > + if (!kfence_sample_interval || __kfence_pool) > > return; > > > > - __kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); > > + __kfence_pool = memblock_alloc_raw(KFENCE_POOL_SIZE, PAGE_SIZE); > > > > if (!__kfence_pool) > > pr_err("failed to allocate pool\n"); > > -- > > 2.31.0 > >
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index e18fbbd5d9b4..65f0210edb65 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -430,6 +430,8 @@ static bool __init kfence_init_pool(void) if (!__kfence_pool) return false; + memset(__kfence_pool, 0, KFENCE_POOL_SIZE); + if (!arch_kfence_init_pool()) goto err; @@ -645,10 +647,10 @@ static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate); void __init kfence_alloc_pool(void) { - if (!kfence_sample_interval) + if (!kfence_sample_interval || __kfence_pool) return; - __kfence_pool = memblock_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); + __kfence_pool = memblock_alloc_raw(KFENCE_POOL_SIZE, PAGE_SIZE); if (!__kfence_pool) pr_err("failed to allocate pool\n");
Some architectures may want to allocate the __kfence_pool differently for example, allocate the __kfence_pool earlier before paging_init(). We also delay the memset() to kfence_init_pool(). Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> --- mm/kfence/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)