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OPP: fix dev_pm_opp_find_bw_*() when bandwidth table not initialized 

[ Upstream commit b44b9bc7cab2967c3d6a791b1cd542c89fc07f0e ]

If a driver calls dev_pm_opp_find_bw_ceil/floor() the retrieve bandwidth
from the OPP table but the bandwidth table was not created because the
interconnect properties were missing in the OPP consumer node, the
kernel will crash with:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
...
pc : _read_bw+0x8/0x10
lr : _opp_table_find_key+0x9c/0x174
...
Call trace:
  _read_bw+0x8/0x10 (P)
  _opp_table_find_key+0x9c/0x174 (L)
  _find_key+0x98/0x168
  dev_pm_opp_find_bw_ceil+0x50/0x88
...

In order to fix the crash, create an assert function to check
if the bandwidth table was created before trying to get a
bandwidth with _read_bw().

Fixes: add1dc094a ("OPP: Use generic key finding helpers for bandwidth key")
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Neil Armstrong 2024-12-03 09:13:00 +01:00 committed by Greg Kroah-Hartman
parent eb6ffa0192
commit 84ff05c9bd
1 changed files with 13 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/opp/core.c
View File

@ -116,6 +116,15 @@ static bool assert_clk_index(struct opp_table *opp_table,
return opp_table->clk_count > index;
}
/*
* Returns true if bandwidth table is large enough to contain the bandwidth index.
*/
static bool assert_bandwidth_index(struct opp_table *opp_table,
unsigned int index)
{
return opp_table->path_count > index;
}
/**
* dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp
* @opp: opp for which voltage has to be returned for
@ -850,7 +859,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev, unsigned int *bw,
unsigned long temp = *bw;
struct dev_pm_opp *opp;
opp = _find_key_ceil(dev, &temp, index, true, _read_bw, NULL);
opp = _find_key_ceil(dev, &temp, index, true, _read_bw,
assert_bandwidth_index);
*bw = temp;
return opp;
}
@ -881,7 +891,8 @@ struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev,
unsigned long temp = *bw;
struct dev_pm_opp *opp;
opp = _find_key_floor(dev, &temp, index, true, _read_bw, NULL);
opp = _find_key_floor(dev, &temp, index, true, _read_bw,
assert_bandwidth_index);
*bw = temp;
return opp;
}