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Message-Id: <1ed0de54ce6021fa0fdf50e938365546a4f5e316.1566925030.git.christophe.leroy@c-s.fr>
Date: Tue, 27 Aug 2019 16:57:29 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
ravi.bangoria@...ux.ibm.com
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 2/2] powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow
any address range size.
Unlike standard powerpc, Powerpc 8xx doesn't have SPRN_DABR, but
it has a breakpoint support based on a set of comparators which
allow more flexibility.
Commit 4ad8622dc548 ("powerpc/8xx: Implement hw_breakpoint")
implemented breakpoints by emulating the DABR behaviour. It did
this by setting one comparator the match 4 bytes at breakpoint address
and the other comparator to match 4 bytes at breakpoint address + 4.
Rewrite 8xx hw_breakpoint to make breakpoints match all addresses
defined by the breakpoint address and length by making full use of
comparators.
Now, comparator E is set to match any address greater than breakpoint
address minus one. Comparator F is set to match any address lower than
breakpoint address plus breakpoint length.
When the breakpoint range starts at address 0, the breakpoint is set
to match comparator F only. When the breakpoint range end at address
0xffffffff, the breakpoint is set to match comparator E only.
Otherwise the breakpoint is set to match comparator E and F.
At the same time, use registers bit names instead of hardcode values.
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
Cc: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
---
arch/powerpc/include/asm/reg_8xx.h | 14 ++++++++++
arch/powerpc/kernel/hw_breakpoint.c | 3 ++
arch/powerpc/kernel/process.c | 55 ++++++++++++++++++++++---------------
3 files changed, 50 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/reg_8xx.h b/arch/powerpc/include/asm/reg_8xx.h
index abc663c0f1db..98e97c22df8b 100644
--- a/arch/powerpc/include/asm/reg_8xx.h
+++ b/arch/powerpc/include/asm/reg_8xx.h
@@ -37,7 +37,21 @@
#define SPRN_CMPE 152
#define SPRN_CMPF 153
#define SPRN_LCTRL1 156
+#define LCTRL1_CTE_GT 0xc0000000
+#define LCTRL1_CTF_LT 0x14000000
+#define LCTRL1_CRWE_RW 0x00000000
+#define LCTRL1_CRWE_RO 0x00040000
+#define LCTRL1_CRWE_WO 0x000c0000
+#define LCTRL1_CRWF_RW 0x00000000
+#define LCTRL1_CRWF_RO 0x00010000
+#define LCTRL1_CRWF_WO 0x00030000
#define SPRN_LCTRL2 157
+#define LCTRL2_LW0EN 0x80000000
+#define LCTRL2_LW0LA_E 0x00000000
+#define LCTRL2_LW0LA_F 0x04000000
+#define LCTRL2_LW0LA_EandF 0x08000000
+#define LCTRL2_LW0LADC 0x02000000
+#define LCTRL2_SLW0EN 0x00000002
#ifdef CONFIG_PPC_8xx
#define SPRN_ICTRL 158
#endif
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 28ad3171bb82..d8bd4dbef561 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -163,6 +163,9 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
*/
if (!ppc_breakpoint_available())
return -ENODEV;
+ /* 8xx can setup a range without limitation */
+ if (IS_ENABLED(CONFIG_PPC_8xx))
+ return 0;
length_max = 8; /* DABR */
if (dawr_enabled()) {
length_max = 512 ; /* 64 doublewords */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 8fc4de0d22b4..79e4f072a746 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -751,28 +751,6 @@ static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
mtspr(SPRN_DABRX, dabrx);
return 0;
}
-#elif defined(CONFIG_PPC_8xx)
-static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
-{
- unsigned long addr = dabr & ~HW_BRK_TYPE_DABR;
- unsigned long lctrl1 = 0x90000000; /* compare type: equal on E & F */
- unsigned long lctrl2 = 0x8e000002; /* watchpoint 1 on cmp E | F */
-
- if ((dabr & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_READ)
- lctrl1 |= 0xa0000;
- else if ((dabr & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_WRITE)
- lctrl1 |= 0xf0000;
- else if ((dabr & HW_BRK_TYPE_RDWR) == 0)
- lctrl2 = 0;
-
- mtspr(SPRN_LCTRL2, 0);
- mtspr(SPRN_CMPE, addr);
- mtspr(SPRN_CMPF, addr + 4);
- mtspr(SPRN_LCTRL1, lctrl1);
- mtspr(SPRN_LCTRL2, lctrl2);
-
- return 0;
-}
#else
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
@@ -793,6 +771,37 @@ static inline int set_dabr(struct arch_hw_breakpoint *brk)
return __set_dabr(dabr, dabrx);
}
+static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
+{
+ unsigned long lctrl1 = LCTRL1_CTE_GT | LCTRL1_CTF_LT | LCTRL1_CRWE_RW |
+ LCTRL1_CRWF_RW;
+ unsigned long lctrl2 = LCTRL2_LW0EN | LCTRL2_LW0LADC | LCTRL2_SLW0EN;
+
+ if (brk->address == 0)
+ lctrl2 |= LCTRL2_LW0LA_F;
+ else if (brk->address + brk->len == 0)
+ lctrl2 |= LCTRL2_LW0LA_E;
+ else
+ lctrl2 |= LCTRL2_LW0LA_EandF;
+
+ mtspr(SPRN_LCTRL2, 0);
+
+ if ((brk->type & HW_BRK_TYPE_RDWR) == 0)
+ return 0;
+
+ if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_READ)
+ lctrl1 |= LCTRL1_CRWE_RO | LCTRL1_CRWF_RO;
+ if ((brk->type & HW_BRK_TYPE_RDWR) == HW_BRK_TYPE_WRITE)
+ lctrl1 |= LCTRL1_CRWE_WO | LCTRL1_CRWF_WO;
+
+ mtspr(SPRN_CMPE, brk->address - 1);
+ mtspr(SPRN_CMPF, brk->address + brk->len);
+ mtspr(SPRN_LCTRL1, lctrl1);
+ mtspr(SPRN_LCTRL2, lctrl2);
+
+ return 0;
+}
+
void __set_breakpoint(struct arch_hw_breakpoint *brk)
{
memcpy(this_cpu_ptr(¤t_brk), brk, sizeof(*brk));
@@ -800,6 +809,8 @@ void __set_breakpoint(struct arch_hw_breakpoint *brk)
if (dawr_enabled())
// Power8 or later
set_dawr(brk);
+ else if (IS_ENABLED(CONFIG_PPC_8xx))
+ set_breakpoint_8xx(brk);
else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
// Power7 or earlier
set_dabr(brk);
--
2.13.3
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