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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-07-02 17:36:04 +0300 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2016-07-02 21:20:06 +0300 |
| commit | 1bbea16a736a1cbf9c1917b472c2b427d4c2a185 (patch) | |
| tree | fed9b18232c832c26de14c38415f29ed524f1256 /drivers/gpu/drm/i915/intel_dsi_pll.c | |
| parent | ebe69dd366dcb6514be78cfdb8e89d9cc2ebb361 (diff) | |
| download | linux-1bbea16a736a1cbf9c1917b472c2b427d4c2a185.tar.xz | |
drm/i915: Fix buffer overflow in dsi_calc_mnp()
smatch complain:
drivers/gpu/drm/i915/intel_dsi_pll.c:101 dsi_calc_mnp() error: buffer
overflow 'lfsr_converts' 39 <= 4294967234
and looks justified in doing so.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1467470166-31717-7-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dsi_pll.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dsi_pll.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c index 4f9930bc89e5..1fcddeb3303d 100644 --- a/drivers/gpu/drm/i915/intel_dsi_pll.c +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c @@ -55,12 +55,10 @@ static int dsi_calc_mnp(struct drm_i915_private *dev_priv, struct intel_crtc_state *config, int target_dsi_clk) { - unsigned int calc_m = 0, calc_p = 0; unsigned int m_min, m_max, p_min = 2, p_max = 6; unsigned int m, n, p; - int ref_clk; - int delta = target_dsi_clk; - u32 m_seed; + unsigned int calc_m, calc_p; + int delta, ref_clk; /* target_dsi_clk is expected in kHz */ if (target_dsi_clk < 300000 || target_dsi_clk > 1150000) { @@ -80,6 +78,10 @@ static int dsi_calc_mnp(struct drm_i915_private *dev_priv, m_max = 92; } + calc_p = p_min; + calc_m = m_min; + delta = abs(target_dsi_clk - (m_min * ref_clk) / (p_min * n)); + for (m = m_min; m <= m_max && delta; m++) { for (p = p_min; p <= p_max && delta; p++) { /* @@ -97,11 +99,10 @@ static int dsi_calc_mnp(struct drm_i915_private *dev_priv, } /* register has log2(N1), this works fine for powers of two */ - n = ffs(n) - 1; - m_seed = lfsr_converts[calc_m - 62]; config->dsi_pll.ctrl = 1 << (DSI_PLL_P1_POST_DIV_SHIFT + calc_p - 2); - config->dsi_pll.div = n << DSI_PLL_N1_DIV_SHIFT | - m_seed << DSI_PLL_M1_DIV_SHIFT; + config->dsi_pll.div = + (ffs(n) - 1) << DSI_PLL_N1_DIV_SHIFT | + (u32)lfsr_converts[calc_m - 62] << DSI_PLL_M1_DIV_SHIFT; return 0; } |