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coresight: etm4x: Detect system instructions support

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ETM v4.4 onwards adds support for system instruction access
to the ETM. Detect the support on an ETM and switch to using the
mode when available.

Link: https://lore.kernel.org/r/20210110224850.1880240-23-suzuki.poulose@arm.com
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210201181351.1475223-25-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Suzuki K Poulose 2021-02-01 11:13:44 -07:00 committed by Greg Kroah-Hartman
parent 1ab3bb9df5
commit dc1747a716
1 changed files with 39 additions and 0 deletions
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39
drivers/hwtracing/coresight/coresight-etm4x-core.c
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@ -782,6 +782,37 @@ static const struct coresight_ops etm4_cs_ops = {
.source_ops = &etm4_source_ops,
};
static inline bool cpu_supports_sysreg_trace(void)
{
u64 dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1);
return ((dfr0 >> ID_AA64DFR0_TRACEVER_SHIFT) & 0xfUL) > 0;
}
static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata,
struct csdev_access *csa)
{
u32 devarch;
if (!cpu_supports_sysreg_trace())
return false;
/*
* ETMs implementing sysreg access must implement TRCDEVARCH.
*/
devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH);
if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH)
return false;
*csa = (struct csdev_access) {
.io_mem = false,
.read = etm4x_sysreg_read,
.write = etm4x_sysreg_write,
};
drvdata->arch = etm_devarch_to_arch(devarch);
return true;
}
static bool etm4_init_iomem_access(struct etmv4_drvdata *drvdata,
struct csdev_access *csa)
{
@ -812,9 +843,17 @@ static bool etm4_init_iomem_access(struct etmv4_drvdata *drvdata,
static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata,
struct csdev_access *csa)
{
/*
* Always choose the memory mapped io, if there is
* a memory map to prevent sysreg access on broken
* systems.
*/
if (drvdata->base)
return etm4_init_iomem_access(drvdata, csa);
if (etm4_init_sysreg_access(drvdata, csa))
return true;
return false;
}