From e08658a657f974590809290c62e889f0fd420200 Mon Sep 17 00:00:00 2001
From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Date: Sat, 22 Feb 2020 13:50:49 +0530
Subject: [PATCH 1/4] powerpc/watchpoint: Don't call dar_within_range() for
Book3S
DAR is set to the first byte of overlap between actual access and
watched range at DSI on Book3S processor. But actual access range
might or might not be within user asked range. So for Book3S, it
must not call dar_within_range().
This revert portion of commit 39413ae00967 ("powerpc/hw_breakpoints:
Rewrite 8xx breakpoints to allow any address range size.").
Before patch:
# ./tools/testing/selftests/powerpc/ptrace/perf-hwbreak
...
TESTED: No overlap
FAILED: Partial overlap: 0 != 2
TESTED: Partial overlap
TESTED: No overlap
FAILED: Full overlap: 0 != 2
failure: perf_hwbreak
After patch:
TESTED: No overlap
TESTED: Partial overlap
TESTED: Partial overlap
TESTED: No overlap
TESTED: Full overlap
success: perf_hwbreak
Fixes: 39413ae00967 ("powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200222082049.330435-1-ravi.bangoria@linux.ibm.com
---
arch/powerpc/kernel/hw_breakpoint.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 2462cd7c565c6..d0854320bb50f 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -331,11 +331,13 @@ int hw_breakpoint_handler(struct die_args *args)
}
info->type &= ~HW_BRK_TYPE_EXTRANEOUS_IRQ;
- if (!dar_within_range(regs->dar, info))
- info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
-
- if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info))
- goto out;
+ if (IS_ENABLED(CONFIG_PPC_8xx)) {
+ if (!dar_within_range(regs->dar, info))
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ } else {
+ if (!stepping_handler(regs, bp, info))
+ goto out;
+ }
/*
* As a policy, the callback is invoked in a 'trigger-after-execute'
From cb0cc635c7a9fa8a3a0f75d4d896721819c63add Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Date: Thu, 20 Feb 2020 17:01:32 +0530
Subject: [PATCH 2/4] powerpc: Include .BTF section
Selecting CONFIG_DEBUG_INFO_BTF results in the below warning from ld:
ld: warning: orphan section `.BTF' from `.btf.vmlinux.bin.o' being placed in section `.BTF'
Include .BTF section in vmlinux explicitly to fix the same.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200220113132.857132-1-naveen.n.rao@linux.vnet.ibm.com
---
arch/powerpc/kernel/vmlinux.lds.S | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index b4c89a1acebb8..a32d478a7f41d 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -303,6 +303,12 @@ SECTIONS
*(.branch_lt)
}
+#ifdef CONFIG_DEBUG_INFO_BTF
+ .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) {
+ *(.BTF)
+ }
+#endif
+
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
__start_opd = .;
KEEP(*(.opd))
From fc37a1632d40c80c067eb1bc235139f5867a2667 Mon Sep 17 00:00:00 2001
From: "Desnes A. Nunes do Rosario" <desnesn@linux.ibm.com>
Date: Thu, 27 Feb 2020 10:47:15 -0300
Subject: [PATCH 3/4] powerpc: fix hardware PMU exception bug on PowerVM
compatibility mode systems
PowerVM systems running compatibility mode on a few Power8 revisions are
still vulnerable to the hardware defect that loses PMU exceptions arriving
prior to a context switch.
The software fix for this issue is enabled through the CPU_FTR_PMAO_BUG
cpu_feature bit, nevertheless this bit also needs to be set for PowerVM
compatibility mode systems.
Fixes: 68f2f0d431d9ea4 ("powerpc: Add a cpu feature CPU_FTR_PMAO_BUG")
Signed-off-by: Desnes A. Nunes do Rosario <desnesn@linux.ibm.com>
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200227134715.9715-1-desnesn@linux.ibm.com
---
arch/powerpc/kernel/cputable.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index e745abc5457a0..245be4fafe134 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -2193,11 +2193,13 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset,
* oprofile_cpu_type already has a value, then we are
* possibly overriding a real PVR with a logical one,
* and, in that case, keep the current value for
- * oprofile_cpu_type.
+ * oprofile_cpu_type. Futhermore, let's ensure that the
+ * fix for the PMAO bug is enabled on compatibility mode.
*/
if (old.oprofile_cpu_type != NULL) {
t->oprofile_cpu_type = old.oprofile_cpu_type;
t->oprofile_type = old.oprofile_type;
+ t->cpu_features |= old.cpu_features & CPU_FTR_PMAO_BUG;
}
}
From 59bee45b9712c759ea4d3dcc4eff1752f3a66558 Mon Sep 17 00:00:00 2001
From: Michael Ellerman <mpe@ellerman.id.au>
Date: Tue, 3 Mar 2020 23:28:47 +1100
Subject: [PATCH 4/4] powerpc/mm: Fix missing KUAP disable in
flush_coherent_icache()
Stefan reported a strange kernel fault which turned out to be due to a
missing KUAP disable in flush_coherent_icache() called from
flush_icache_range().
The fault looks like:
Kernel attempted to access user page (7fffc30d9c00) - exploit attempt? (uid: 1009)
BUG: Unable to handle kernel data access on read at 0x7fffc30d9c00
Faulting instruction address: 0xc00000000007232c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
CPU: 35 PID: 5886 Comm: sigtramp Not tainted 5.6.0-rc2-gcc-8.2.0-00003-gfc37a1632d40 #79
NIP: c00000000007232c LR: c00000000003b7fc CTR: 0000000000000000
REGS: c000001e11093940 TRAP: 0300 Not tainted (5.6.0-rc2-gcc-8.2.0-00003-gfc37a1632d40)
MSR: 900000000280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28000884 XER: 00000000
CFAR: c0000000000722fc DAR: 00007fffc30d9c00 DSISR: 08000000 IRQMASK: 0
GPR00: c00000000003b7fc c000001e11093bd0 c0000000023ac200 00007fffc30d9c00
GPR04: 00007fffc30d9c18 0000000000000000 c000001e11093bd4 0000000000000000
GPR08: 0000000000000000 0000000000000001 0000000000000000 c000001e1104ed80
GPR12: 0000000000000000 c000001fff6ab380 c0000000016be2d0 4000000000000000
GPR16: c000000000000000 bfffffffffffffff 0000000000000000 0000000000000000
GPR20: 00007fffc30d9c00 00007fffc30d8f58 00007fffc30d9c18 00007fffc30d9c20
GPR24: 00007fffc30d9c18 0000000000000000 c000001e11093d90 c000001e1104ed80
GPR28: c000001e11093e90 0000000000000000 c0000000023d9d18 00007fffc30d9c00
NIP flush_icache_range+0x5c/0x80
LR handle_rt_signal64+0x95c/0xc2c
Call Trace:
0xc000001e11093d90 (unreliable)
handle_rt_signal64+0x93c/0xc2c
do_notify_resume+0x310/0x430
ret_from_except_lite+0x70/0x74
Instruction dump:
409e002c 7c0802a6 3c62ff31 3863f6a0 f8010080 48195fed 60000000 48fe4c8d
60000000 e8010080 7c0803a6 7c0004ac <7c00ffac> 7c0004ac 4c00012c 38210070
This path through handle_rt_signal64() to setup_trampoline() and
flush_icache_range() is only triggered by 64-bit processes that have
unmapped their VDSO, which is rare.
flush_icache_range() takes a range of addresses to flush. In
flush_coherent_icache() we implement an optimisation for CPUs where we
know we don't actually have to flush the whole range, we just need to
do a single icbi.
However we still execute the icbi on the user address of the start of
the range we're flushing. On CPUs that also implement KUAP (Power9)
that leads to the spurious fault above.
We should be able to pass any address, including a kernel address, to
the icbi on these CPUs, which would avoid any interaction with KUAP.
But I don't want to make that change in a bug fix, just in case it
surfaces some strange behaviour on some CPU.
So for now just disable KUAP around the icbi. Note the icbi is treated
as a load, so we allow read access, not write as you'd expect.
Fixes: 890274c2dc4c ("powerpc/64s: Implement KUAP for Radix MMU")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200303235708.26004-1-mpe@ellerman.id.au
---
arch/powerpc/mm/mem.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index ef7b1119b2e29..1c07d5a3f5431 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -373,7 +373,9 @@ static inline bool flush_coherent_icache(unsigned long addr)
*/
if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
mb(); /* sync */
+ allow_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
icbi((void *)addr);
+ prevent_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
mb(); /* sync */
isync();
return true;