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Message-Id: <20220623174131.3818333-1-ndesaulniers@google.com>
Date: Thu, 23 Jun 2022 10:41:31 -0700
From: Nick Desaulniers <ndesaulniers@...gle.com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>,
Suzuki K Poulose <suzuki.poulose@....com>
Cc: Nick Desaulniers <ndesaulniers@...gle.com>,
Arnd Bergmann <arnd@...nel.org>,
Tao Zhang <quic_taozha@...cinc.com>,
Mike Leach <mike.leach@...aro.org>,
Leo Yan <leo.yan@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Nathan Chancellor <nathan@...nel.org>,
Tom Rix <trix@...hat.com>, coresight@...ts.linaro.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
llvm@...ts.linux.dev
Subject: [PATCH v5] coresight: etm4x: avoid build failure with unrolled loops
When the following configs are enabled:
* CORESIGHT
* CORESIGHT_SOURCE_ETM4X
* UBSAN
* UBSAN_TRAP
Clang fails assemble the kernel with the error:
<instantiation>:1:7: error: expected constant expression in '.inst' directive
.inst (0xd5200000|((((2) << 19) | ((1) << 16) | (((((((((((0x160 + (i * 4))))) >> 2))) >> 7) & 0x7)) << 12) | ((((((((((0x160 + (i * 4))))) >> 2))) & 0xf)) << 8) | (((((((((((0x160 + (i * 4))))) >> 2))) >> 4) & 0x7)) << 5)))|(.L__reg_num_x8))
^
drivers/hwtracing/coresight/coresight-etm4x-core.c:702:4: note: while in
macro instantiation
etm4x_relaxed_read32(csa, TRCCNTVRn(i));
^
drivers/hwtracing/coresight/coresight-etm4x.h:403:4: note: expanded from
macro 'etm4x_relaxed_read32'
read_etm4x_sysreg_offset((offset), false)))
^
drivers/hwtracing/coresight/coresight-etm4x.h:383:12: note: expanded
from macro 'read_etm4x_sysreg_offset'
__val = read_etm4x_sysreg_const_offset((offset)); \
^
drivers/hwtracing/coresight/coresight-etm4x.h:149:2: note: expanded from
macro 'read_etm4x_sysreg_const_offset'
READ_ETM4x_REG(ETM4x_OFFSET_TO_REG(offset))
^
drivers/hwtracing/coresight/coresight-etm4x.h:144:2: note: expanded from
macro 'READ_ETM4x_REG'
read_sysreg_s(ETM4x_REG_NUM_TO_SYSREG((reg)))
^
arch/arm64/include/asm/sysreg.h:1108:15: note: expanded from macro
'read_sysreg_s'
asm volatile(__mrs_s("%0", r) : "=r" (__val)); \
^
arch/arm64/include/asm/sysreg.h:1074:2: note: expanded from macro '__mrs_s'
" mrs_s " v ", " __stringify(r) "\n" \
^
Consider the definitions of TRCSSCSRn and TRCCNTVRn:
drivers/hwtracing/coresight/coresight-etm4x.h:56
#define TRCCNTVRn(n) (0x160 + (n * 4))
drivers/hwtracing/coresight/coresight-etm4x.h:81
#define TRCSSCSRn(n) (0x2A0 + (n * 4))
Where the macro parameter is expanded to i; a loop induction variable
from etm4_disable_hw.
When any compiler can determine that loops may be unrolled, then the
__builtin_constant_p check in read_etm4x_sysreg_offset() defined in
drivers/hwtracing/coresight/coresight-etm4x.h may evaluate to true. This
can lead to the expression `(0x160 + (i * 4))` being passed to
read_etm4x_sysreg_const_offset. Via the trace above, this is passed
through READ_ETM4x_REG, read_sysreg_s, and finally to __mrs_s where it
is string-ified and used directly in inline asm.
Regardless of which compiler or compiler options determine whether a
loop can or can't be unrolled, which determines whether
__builtin_constant_p evaluates to true when passed an expression using a
loop induction variable, it is NEVER safe to allow the preprocessor to
construct inline asm like:
asm volatile (".inst (0x160 + (i * 4))" : "=r"(__val));
^ expected constant expression
Replace unsafe uses of calls to etm4x_relaxed_read32 with
csdev_access_relaxed_read32 when the parameter is an expression that
would be invalid inline asm so that it does not depend on the ability of
the compiler to optimize __builtin_constant_p of the expression to true.
Only when the second parameter of etm4x_relaxed_read32 expands to an
expression dependent on a loop induction variable do we need to fix
this.
For such cases where the induction variable is used in an expression,
perform the following function call replacements:
* etm4x_relaxed_write32 -> csdev_access_relaxed_write32
* etm4x_relaxed_write64 -> csdev_access_relaxed_write64
* etm4x_relaxed_read32 -> csdev_access_relaxed_read32
* etm4x_read32 -> csdev_access_read32
* etm4x_read64 -> csdev_access_read64
This is not a bug in clang; it's a potentially unsafe use of the macro
arguments in read_etm4x_sysreg_offset dependent on __builtin_constant_p.
Link: https://github.com/ClangBuiltLinux/linux/issues/1310
Reported-by: Arnd Bergmann <arnd@...nel.org>
Suggested-by: Arnd Bergmann <arnd@...nel.org>
Suggested-by: Tao Zhang <quic_taozha@...cinc.com>
Suggested-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
---
Changes v4 -> v5:
* Also change etm4x_relaxed_write32, etm4x_relaxed_write64,
etm4x_read32, and etm4x_read64 as per Suzuki.
* Fix some typos in commit message.
* Add Arnd's reported-by tag.
* Reformat with `git-clang-format HEAD~` since the new fn's have long
identifiers.
* Wrap the error message in the commit message.
V4 (Nick):
https://lore.kernel.org/llvm/20220614220229.1640085-1-ndesaulniers@google.com/
V3 (Tao):
https://lore.kernel.org/lkml/1632652550-26048-1-git-send-email-quic_taozha@quicinc.com/
V2 (Arnd):
https://lore.kernel.org/lkml/20210429145752.3218324-1-arnd@kernel.org/
V1 (Arnd):
https://lore.kernel.org/lkml/20210225094324.3542511-1-arnd@kernel.org/
.../coresight/coresight-etm4x-core.c | 104 +++++++++++-------
1 file changed, 65 insertions(+), 39 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 87299e99dabb..f5391d33dd4d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -423,14 +423,18 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
if (drvdata->nr_pe_cmp)
etm4x_relaxed_write32(csa, config->vipcssctlr, TRCVIPCSSCTLR);
for (i = 0; i < drvdata->nrseqstate - 1; i++)
- etm4x_relaxed_write32(csa, config->seq_ctrl[i], TRCSEQEVRn(i));
+ csdev_access_relaxed_write32(csa, config->seq_ctrl[i],
+ TRCSEQEVRn(i));
etm4x_relaxed_write32(csa, config->seq_rst, TRCSEQRSTEVR);
etm4x_relaxed_write32(csa, config->seq_state, TRCSEQSTR);
etm4x_relaxed_write32(csa, config->ext_inp, TRCEXTINSELR);
for (i = 0; i < drvdata->nr_cntr; i++) {
- etm4x_relaxed_write32(csa, config->cntrldvr[i], TRCCNTRLDVRn(i));
- etm4x_relaxed_write32(csa, config->cntr_ctrl[i], TRCCNTCTLRn(i));
- etm4x_relaxed_write32(csa, config->cntr_val[i], TRCCNTVRn(i));
+ csdev_access_relaxed_write32(csa, config->cntrldvr[i],
+ TRCCNTRLDVRn(i));
+ csdev_access_relaxed_write32(csa, config->cntr_ctrl[i],
+ TRCCNTCTLRn(i));
+ csdev_access_relaxed_write32(csa, config->cntr_val[i],
+ TRCCNTVRn(i));
}
/*
@@ -438,29 +442,37 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
* such start at 2.
*/
for (i = 2; i < drvdata->nr_resource * 2; i++)
- etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i));
+ csdev_access_relaxed_write32(csa, config->res_ctrl[i],
+ TRCRSCTLRn(i));
for (i = 0; i < drvdata->nr_ss_cmp; i++) {
/* always clear status bit on restart if using single-shot */
if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
config->ss_status[i] &= ~TRCSSCSRn_STATUS;
- etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i));
- etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i));
+ csdev_access_relaxed_write32(csa, config->ss_ctrl[i],
+ TRCSSCCRn(i));
+ csdev_access_relaxed_write32(csa, config->ss_status[i],
+ TRCSSCSRn(i));
if (etm4x_sspcicrn_present(drvdata, i))
- etm4x_relaxed_write32(csa, config->ss_pe_cmp[i], TRCSSPCICRn(i));
+ csdev_access_relaxed_write32(csa, config->ss_pe_cmp[i],
+ TRCSSPCICRn(i));
}
for (i = 0; i < drvdata->nr_addr_cmp; i++) {
- etm4x_relaxed_write64(csa, config->addr_val[i], TRCACVRn(i));
- etm4x_relaxed_write64(csa, config->addr_acc[i], TRCACATRn(i));
+ csdev_access_relaxed_write64(csa, config->addr_val[i],
+ TRCACVRn(i));
+ csdev_access_relaxed_write64(csa, config->addr_acc[i],
+ TRCACATRn(i));
}
for (i = 0; i < drvdata->numcidc; i++)
- etm4x_relaxed_write64(csa, config->ctxid_pid[i], TRCCIDCVRn(i));
+ csdev_access_relaxed_write64(csa, config->ctxid_pid[i],
+ TRCCIDCVRn(i));
etm4x_relaxed_write32(csa, config->ctxid_mask0, TRCCIDCCTLR0);
if (drvdata->numcidc > 4)
etm4x_relaxed_write32(csa, config->ctxid_mask1, TRCCIDCCTLR1);
for (i = 0; i < drvdata->numvmidc; i++)
- etm4x_relaxed_write64(csa, config->vmid_val[i], TRCVMIDCVRn(i));
+ csdev_access_relaxed_write64(csa, config->vmid_val[i],
+ TRCVMIDCVRn(i));
etm4x_relaxed_write32(csa, config->vmid_mask0, TRCVMIDCCTLR0);
if (drvdata->numvmidc > 4)
etm4x_relaxed_write32(csa, config->vmid_mask1, TRCVMIDCCTLR1);
@@ -836,13 +848,13 @@ static void etm4_disable_hw(void *info)
/* read the status of the single shot comparators */
for (i = 0; i < drvdata->nr_ss_cmp; i++) {
config->ss_status[i] =
- etm4x_relaxed_read32(csa, TRCSSCSRn(i));
+ csdev_access_relaxed_read32(csa, TRCSSCSRn(i));
}
/* read back the current counter values */
for (i = 0; i < drvdata->nr_cntr; i++) {
config->cntr_val[i] =
- etm4x_relaxed_read32(csa, TRCCNTVRn(i));
+ csdev_access_relaxed_read32(csa, TRCCNTVRn(i));
}
coresight_disclaim_device_unlocked(csdev);
@@ -1177,7 +1189,7 @@ static void etm4_init_arch_data(void *info)
drvdata->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
for (i = 0; i < drvdata->nr_ss_cmp; i++) {
drvdata->config.ss_status[i] =
- etm4x_relaxed_read32(csa, TRCSSCSRn(i));
+ csdev_access_relaxed_read32(csa, TRCSSCSRn(i));
}
/* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
drvdata->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
@@ -1615,31 +1627,33 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
state->trcvdarcctlr = etm4x_read32(csa, TRCVDARCCTLR);
for (i = 0; i < drvdata->nrseqstate - 1; i++)
- state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i));
+ state->trcseqevr[i] = csdev_access_read32(csa, TRCSEQEVRn(i));
state->trcseqrstevr = etm4x_read32(csa, TRCSEQRSTEVR);
state->trcseqstr = etm4x_read32(csa, TRCSEQSTR);
state->trcextinselr = etm4x_read32(csa, TRCEXTINSELR);
for (i = 0; i < drvdata->nr_cntr; i++) {
- state->trccntrldvr[i] = etm4x_read32(csa, TRCCNTRLDVRn(i));
- state->trccntctlr[i] = etm4x_read32(csa, TRCCNTCTLRn(i));
- state->trccntvr[i] = etm4x_read32(csa, TRCCNTVRn(i));
+ state->trccntrldvr[i] =
+ csdev_access_read32(csa, TRCCNTRLDVRn(i));
+ state->trccntctlr[i] = csdev_access_read32(csa, TRCCNTCTLRn(i));
+ state->trccntvr[i] = csdev_access_read32(csa, TRCCNTVRn(i));
}
for (i = 0; i < drvdata->nr_resource * 2; i++)
- state->trcrsctlr[i] = etm4x_read32(csa, TRCRSCTLRn(i));
+ state->trcrsctlr[i] = csdev_access_read32(csa, TRCRSCTLRn(i));
for (i = 0; i < drvdata->nr_ss_cmp; i++) {
- state->trcssccr[i] = etm4x_read32(csa, TRCSSCCRn(i));
- state->trcsscsr[i] = etm4x_read32(csa, TRCSSCSRn(i));
+ state->trcssccr[i] = csdev_access_read32(csa, TRCSSCCRn(i));
+ state->trcsscsr[i] = csdev_access_read32(csa, TRCSSCSRn(i));
if (etm4x_sspcicrn_present(drvdata, i))
- state->trcsspcicr[i] = etm4x_read32(csa, TRCSSPCICRn(i));
+ state->trcsspcicr[i] =
+ csdev_access_read32(csa, TRCSSPCICRn(i));
}
for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
- state->trcacvr[i] = etm4x_read64(csa, TRCACVRn(i));
- state->trcacatr[i] = etm4x_read64(csa, TRCACATRn(i));
+ state->trcacvr[i] = csdev_access_read64(csa, TRCACVRn(i));
+ state->trcacatr[i] = csdev_access_read64(csa, TRCACATRn(i));
}
/*
@@ -1650,10 +1664,10 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
*/
for (i = 0; i < drvdata->numcidc; i++)
- state->trccidcvr[i] = etm4x_read64(csa, TRCCIDCVRn(i));
+ state->trccidcvr[i] = csdev_access_read64(csa, TRCCIDCVRn(i));
for (i = 0; i < drvdata->numvmidc; i++)
- state->trcvmidcvr[i] = etm4x_read64(csa, TRCVMIDCVRn(i));
+ state->trcvmidcvr[i] = csdev_access_read64(csa, TRCVMIDCVRn(i));
state->trccidcctlr0 = etm4x_read32(csa, TRCCIDCCTLR0);
if (drvdata->numcidc > 4)
@@ -1744,38 +1758,50 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
etm4x_relaxed_write32(csa, state->trcvdarcctlr, TRCVDARCCTLR);
for (i = 0; i < drvdata->nrseqstate - 1; i++)
- etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i));
+ csdev_access_relaxed_write32(csa, state->trcseqevr[i],
+ TRCSEQEVRn(i));
etm4x_relaxed_write32(csa, state->trcseqrstevr, TRCSEQRSTEVR);
etm4x_relaxed_write32(csa, state->trcseqstr, TRCSEQSTR);
etm4x_relaxed_write32(csa, state->trcextinselr, TRCEXTINSELR);
for (i = 0; i < drvdata->nr_cntr; i++) {
- etm4x_relaxed_write32(csa, state->trccntrldvr[i], TRCCNTRLDVRn(i));
- etm4x_relaxed_write32(csa, state->trccntctlr[i], TRCCNTCTLRn(i));
- etm4x_relaxed_write32(csa, state->trccntvr[i], TRCCNTVRn(i));
+ csdev_access_relaxed_write32(csa, state->trccntrldvr[i],
+ TRCCNTRLDVRn(i));
+ csdev_access_relaxed_write32(csa, state->trccntctlr[i],
+ TRCCNTCTLRn(i));
+ csdev_access_relaxed_write32(csa, state->trccntvr[i],
+ TRCCNTVRn(i));
}
for (i = 0; i < drvdata->nr_resource * 2; i++)
- etm4x_relaxed_write32(csa, state->trcrsctlr[i], TRCRSCTLRn(i));
+ csdev_access_relaxed_write32(csa, state->trcrsctlr[i],
+ TRCRSCTLRn(i));
for (i = 0; i < drvdata->nr_ss_cmp; i++) {
- etm4x_relaxed_write32(csa, state->trcssccr[i], TRCSSCCRn(i));
- etm4x_relaxed_write32(csa, state->trcsscsr[i], TRCSSCSRn(i));
+ csdev_access_relaxed_write32(csa, state->trcssccr[i],
+ TRCSSCCRn(i));
+ csdev_access_relaxed_write32(csa, state->trcsscsr[i],
+ TRCSSCSRn(i));
if (etm4x_sspcicrn_present(drvdata, i))
- etm4x_relaxed_write32(csa, state->trcsspcicr[i], TRCSSPCICRn(i));
+ csdev_access_relaxed_write32(csa, state->trcsspcicr[i],
+ TRCSSPCICRn(i));
}
for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
- etm4x_relaxed_write64(csa, state->trcacvr[i], TRCACVRn(i));
- etm4x_relaxed_write64(csa, state->trcacatr[i], TRCACATRn(i));
+ csdev_access_relaxed_write64(csa, state->trcacvr[i],
+ TRCACVRn(i));
+ csdev_access_relaxed_write64(csa, state->trcacatr[i],
+ TRCACATRn(i));
}
for (i = 0; i < drvdata->numcidc; i++)
- etm4x_relaxed_write64(csa, state->trccidcvr[i], TRCCIDCVRn(i));
+ csdev_access_relaxed_write64(csa, state->trccidcvr[i],
+ TRCCIDCVRn(i));
for (i = 0; i < drvdata->numvmidc; i++)
- etm4x_relaxed_write64(csa, state->trcvmidcvr[i], TRCVMIDCVRn(i));
+ csdev_access_relaxed_write64(csa, state->trcvmidcvr[i],
+ TRCVMIDCVRn(i));
etm4x_relaxed_write32(csa, state->trccidcctlr0, TRCCIDCCTLR0);
if (drvdata->numcidc > 4)
base-commit: 399bd66e219e331976fe6fa6ab81a023c0c97870
--
2.37.0.rc0.104.g0611611a94-goog
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