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pwm: pwm_mchp_xec: fix potential out of bound access

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Fix an issue discovered by Coverity where there is a potential
out of bound access on the divisor arrays.

Fixes #20495
Fixes #20496

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2019-11-26 11:03:30 -08:00 • committed by Anas Nashif
commit ceb2303dd0
1 changed files with 6 additions and 4 deletions
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10
drivers/pwm/pwm_mchp_xec.c
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@ -59,7 +59,9 @@ struct xec_params {
u8_t div; u8_t div;
}; };
u32_t max_freq_high_on_div[16] = { #define NUM_DIV_ELEMS 16
u32_t max_freq_high_on_div[NUM_DIV_ELEMS] = {
48000000, 48000000,
24000000, 24000000,
16000000, 16000000,
@ -78,7 +80,7 @@ u32_t max_freq_high_on_div[16] = {
3000000 3000000
}; };
u32_t max_freq_low_on_div[16] = { u32_t max_freq_low_on_div[NUM_DIV_ELEMS] = {
100000, 100000,
50000, 50000,
33333, 33333,
@ -200,14 +202,14 @@ static struct xec_params *xec_compare_params(u32_t target_freq,
u32_t freq_h = 0; u32_t freq_h = 0;
u32_t freq_l = 0; u32_t freq_l = 0;
if (hc_params->div < UINT8_MAX) { if (hc_params->div < NUM_DIV_ELEMS) {
freq_h = xec_compute_frequency( freq_h = xec_compute_frequency(
max_freq_high_on_div[hc_params->div], max_freq_high_on_div[hc_params->div],
hc_params->on, hc_params->on,
hc_params->off); hc_params->off);
} }
if (lc_params->div < UINT8_MAX) { if (lc_params->div < NUM_DIV_ELEMS) {
freq_l = xec_compute_frequency( freq_l = xec_compute_frequency(
max_freq_low_on_div[lc_params->div], max_freq_low_on_div[lc_params->div],
lc_params->on, lc_params->on,