From 19c383affd5866fffe7646b913aa78cbdd608325 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 23 Mar 2021 14:04:20 +0100 Subject: [PATCH] amdgpu: fix gcc -Wrestrict warning gcc warns about an sprintf() that uses the same buffer as source and destination, which is undefined behavior in C99: drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c: In function 'amdgpu_securedisplay_debugfs_write': drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:141:6: error: 'sprintf' argument 3 overlaps destination object 'i2c_output' [-Werror=restrict] 141 | sprintf(i2c_output, "%s 0x%X", i2c_output, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 142 | securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c:97:7: note: destination object referenced by 'restrict'-qualified argument 1 was declared here 97 | char i2c_output[256]; | ^~~~~~~~~~ Rewrite it to remember the current offset into the buffer instead. Signed-off-by: Arnd Bergmann Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c index 9cf856c..1e59901 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_securedisplay.c @@ -139,9 +139,10 @@ static ssize_t amdgpu_securedisplay_debugfs_write(struct file *f, const char __u ret = psp_securedisplay_invoke(psp, TA_SECUREDISPLAY_COMMAND__SEND_ROI_CRC); if (!ret) { if (securedisplay_cmd->status == TA_SECUREDISPLAY_STATUS__SUCCESS) { + int pos = 0; memset(i2c_output, 0, sizeof(i2c_output)); for (i = 0; i < TA_SECUREDISPLAY_I2C_BUFFER_SIZE; i++) - sprintf(i2c_output, "%s 0x%X", i2c_output, + pos += sprintf(i2c_output + pos, " 0x%X", securedisplay_cmd->securedisplay_out_message.send_roi_crc.i2c_buf[i]); dev_info(adev->dev, "SECUREDISPLAY: I2C buffer out put is :%s\n", i2c_output); } else { -- 2.7.4