From patchwork Tue Jun 10 09:24:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 895597 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 184AB28A717; Tue, 10 Jun 2025 09:24:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749547491; cv=none; b=Ebx6p+lan9BCk5hE3daomOBFNRutcgrZfXM3AKvf/sM517EKqTkzUOO9D2oal/+9tveyJzk6Jlt9OKaj5y+1pz77nzzasmJLG9VmLT2UqmmNUWv6CV8cokRCNoIPCy8bNo1CF9zHOydcZ8eHNOpfyDEkdkajvpH5ZiWSUQw/h0A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749547491; c=relaxed/simple; bh=UBk0O2NifEtSzMDABHTsAPAX1ZK2mbR0B7xvcIeNcf8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gZ9a9au3e7C2SnDxC0q8+FVsxb/ATtBPRpeoo2yR0CRzV7f21BTE3+Mngw2GJ/dcSmNjDa9PvVHAaxNAVWw+SP5y2XEaf1Zi+O4OLs9RW7+V5nR2xPaBhb85514QghrUGuVlf0SNskTnDSSSRPtOyh+JzRB0N86ItlcMjU0QB6g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Myqq29bq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Myqq29bq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 204CCC4CEF2; Tue, 10 Jun 2025 09:24:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749547490; bh=UBk0O2NifEtSzMDABHTsAPAX1ZK2mbR0B7xvcIeNcf8=; h=From:To:Cc:Subject:Date:From; b=Myqq29bqNFixpWKhm/vniAjB5U014iroW5V6KSeHjzQGaWHj3SYAmrn0ZaD1YhweC /LGwo5D0eiLO0PiSTcfzBObyXlVVbPIlzfig7zqvpS8FxtWnCSnAjDBs8lvOOUyzhQ Ef3oUMVFOtc1erwpOTuMcBYCEXnCc5Go0+rzrP5ErieBD+pL1lbNhONK/BqYjXjUNE SiE8W9AtH27iDKHwhasFK88jCXuhuA+jVlxWBMUwliUGA/NP4EtYAMntjlg7QIja4b 79wjTtrTO8Q6pjpbDKOgtNB27F23VMp/Wio3JXY9BJF6v+BOjJZymFb+7ryc3EgRVf JsEnvS3LeQZTw== From: Arnd Bergmann To: Andy Shevchenko , Greg Kroah-Hartman Cc: Arnd Bergmann , Riyan Dhiman , Thomas Zimmermann , Paolo Perego , Lorenzo Stoakes , "Matthew Wilcox (Oracle)" , Jeff Johnson , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] fbtft: reduce stack usage Date: Tue, 10 Jun 2025 11:24:38 +0200 Message-Id: <20250610092445.2640575-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Arnd Bergmann The use of vararg function pointers combined with a huge number of arguments causes some configurations to exceed the stack size warning limit: drivers/staging/fbtft/fbtft-core.c:863:12: error: stack frame size (1512) exceeds limit (1280) in 'fbtft_init_display_from_property' [-Werror,-Wframe-larger-than] drivers/staging/fbtft/fb_ssd1331.c:131:30: error: stack frame size (1392) exceeds limit (1280) in 'set_gamma' [-Werror,-Wframe-larger-than] ^ drivers/staging/fbtft/fb_ssd1351.c:120:30: error: stack frame size (1392) exceeds limit (1280) in 'set_gamma' [-Werror,-Wframe-larger-than] Move the varargs handling into a separate noinline function so each individual function stays below the limit. A better approach might be to replace the varargs function with one that takes an array of arguments, but that would be a much larger rework of the other callers. Signed-off-by: Arnd Bergmann --- drivers/staging/fbtft/fb_ssd1331.c | 36 ++++++++++++------ drivers/staging/fbtft/fb_ssd1351.c | 42 ++++++++++++--------- drivers/staging/fbtft/fbtft-core.c | 59 +++++++++++++----------------- 3 files changed, 73 insertions(+), 64 deletions(-) diff --git a/drivers/staging/fbtft/fb_ssd1331.c b/drivers/staging/fbtft/fb_ssd1331.c index 06b7056d6c71..f43ee3249175 100644 --- a/drivers/staging/fbtft/fb_ssd1331.c +++ b/drivers/staging/fbtft/fb_ssd1331.c @@ -107,6 +107,28 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...) va_end(args); } +static noinline_for_stack void write_gamma_reg(struct fbtft_par *par, + u32 gamma[63]) +{ + write_reg(par, 0xB8, + gamma[0], gamma[1], gamma[2], gamma[3], + gamma[4], gamma[5], gamma[6], gamma[7], + gamma[8], gamma[9], gamma[10], gamma[11], + gamma[12], gamma[13], gamma[14], gamma[15], + gamma[16], gamma[17], gamma[18], gamma[19], + gamma[20], gamma[21], gamma[22], gamma[23], + gamma[24], gamma[25], gamma[26], gamma[27], + gamma[28], gamma[29], gamma[30], gamma[31], + gamma[32], gamma[33], gamma[34], gamma[35], + gamma[36], gamma[37], gamma[38], gamma[39], + gamma[40], gamma[41], gamma[42], gamma[43], + gamma[44], gamma[45], gamma[46], gamma[47], + gamma[48], gamma[49], gamma[50], gamma[51], + gamma[52], gamma[53], gamma[54], gamma[55], + gamma[56], gamma[57], gamma[58], gamma[59], + gamma[60], gamma[61], gamma[62]); +} + /* * Grayscale Lookup Table * GS1 - GS63 @@ -130,7 +152,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...) */ static int set_gamma(struct fbtft_par *par, u32 *curves) { - unsigned long tmp[GAMMA_NUM * GAMMA_LEN]; + u32 tmp[GAMMA_NUM * GAMMA_LEN]; int i, acc = 0; for (i = 0; i < 63; i++) { @@ -150,17 +172,7 @@ static int set_gamma(struct fbtft_par *par, u32 *curves) } } - write_reg(par, 0xB8, - tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6], - tmp[7], tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13], - tmp[14], tmp[15], tmp[16], tmp[17], tmp[18], tmp[19], tmp[20], - tmp[21], tmp[22], tmp[23], tmp[24], tmp[25], tmp[26], tmp[27], - tmp[28], tmp[29], tmp[30], tmp[31], tmp[32], tmp[33], tmp[34], - tmp[35], tmp[36], tmp[37], tmp[38], tmp[39], tmp[40], tmp[41], - tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47], tmp[48], - tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55], - tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61], - tmp[62]); + write_gamma_reg(par, tmp); return 0; } diff --git a/drivers/staging/fbtft/fb_ssd1351.c b/drivers/staging/fbtft/fb_ssd1351.c index 6736b09b2f45..eb8bee6993c3 100644 --- a/drivers/staging/fbtft/fb_ssd1351.c +++ b/drivers/staging/fbtft/fb_ssd1351.c @@ -96,6 +96,28 @@ static int set_var(struct fbtft_par *par) return 0; } +static noinline_for_stack void write_gamma_reg(struct fbtft_par *par, + u32 gamma[63]) +{ + write_reg(par, 0xB8, + gamma[0], gamma[1], gamma[2], gamma[3], + gamma[4], gamma[5], gamma[6], gamma[7], + gamma[8], gamma[9], gamma[10], gamma[11], + gamma[12], gamma[13], gamma[14], gamma[15], + gamma[16], gamma[17], gamma[18], gamma[19], + gamma[20], gamma[21], gamma[22], gamma[23], + gamma[24], gamma[25], gamma[26], gamma[27], + gamma[28], gamma[29], gamma[30], gamma[31], + gamma[32], gamma[33], gamma[34], gamma[35], + gamma[36], gamma[37], gamma[38], gamma[39], + gamma[40], gamma[41], gamma[42], gamma[43], + gamma[44], gamma[45], gamma[46], gamma[47], + gamma[48], gamma[49], gamma[50], gamma[51], + gamma[52], gamma[53], gamma[54], gamma[55], + gamma[56], gamma[57], gamma[58], gamma[59], + gamma[60], gamma[61], gamma[62]); +} + /* * Grayscale Lookup Table * GS1 - GS63 @@ -119,7 +141,7 @@ static int set_var(struct fbtft_par *par) */ static int set_gamma(struct fbtft_par *par, u32 *curves) { - unsigned long tmp[GAMMA_NUM * GAMMA_LEN]; + u32 tmp[GAMMA_NUM * GAMMA_LEN]; int i, acc = 0; for (i = 0; i < 63; i++) { @@ -139,23 +161,7 @@ static int set_gamma(struct fbtft_par *par, u32 *curves) } } - write_reg(par, 0xB8, - tmp[0], tmp[1], tmp[2], tmp[3], - tmp[4], tmp[5], tmp[6], tmp[7], - tmp[8], tmp[9], tmp[10], tmp[11], - tmp[12], tmp[13], tmp[14], tmp[15], - tmp[16], tmp[17], tmp[18], tmp[19], - tmp[20], tmp[21], tmp[22], tmp[23], - tmp[24], tmp[25], tmp[26], tmp[27], - tmp[28], tmp[29], tmp[30], tmp[31], - tmp[32], tmp[33], tmp[34], tmp[35], - tmp[36], tmp[37], tmp[38], tmp[39], - tmp[40], tmp[41], tmp[42], tmp[43], - tmp[44], tmp[45], tmp[46], tmp[47], - tmp[48], tmp[49], tmp[50], tmp[51], - tmp[52], tmp[53], tmp[54], tmp[55], - tmp[56], tmp[57], tmp[58], tmp[59], - tmp[60], tmp[61], tmp[62]); + write_gamma_reg(par, tmp); return 0; } diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c index da9c64152a60..86c77f996f5b 100644 --- a/drivers/staging/fbtft/fbtft-core.c +++ b/drivers/staging/fbtft/fbtft-core.c @@ -833,6 +833,28 @@ int fbtft_unregister_framebuffer(struct fb_info *fb_info) } EXPORT_SYMBOL(fbtft_unregister_framebuffer); +static noinline_for_stack void fbtft_write_register_64(struct fbtft_par *par, + int i, int buf[64]) +{ + par->fbtftops.write_register(par, i, + buf[0], buf[1], buf[2], buf[3], + buf[4], buf[5], buf[6], buf[7], + buf[8], buf[9], buf[10], buf[11], + buf[12], buf[13], buf[14], buf[15], + buf[16], buf[17], buf[18], buf[19], + buf[20], buf[21], buf[22], buf[23], + buf[24], buf[25], buf[26], buf[27], + buf[28], buf[29], buf[30], buf[31], + buf[32], buf[33], buf[34], buf[35], + buf[36], buf[37], buf[38], buf[39], + buf[40], buf[41], buf[42], buf[43], + buf[44], buf[45], buf[46], buf[47], + buf[48], buf[49], buf[50], buf[51], + buf[52], buf[53], buf[54], buf[55], + buf[56], buf[57], buf[58], buf[59], + buf[60], buf[61], buf[62], buf[63]); +} + /** * fbtft_init_display_from_property() - Device Tree init_display() function * @par: Driver data @@ -887,23 +909,8 @@ static int fbtft_init_display_from_property(struct fbtft_par *par) fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "buf[%d] = %02X\n", j, buf[j]); - par->fbtftops.write_register(par, i, - buf[0], buf[1], buf[2], buf[3], - buf[4], buf[5], buf[6], buf[7], - buf[8], buf[9], buf[10], buf[11], - buf[12], buf[13], buf[14], buf[15], - buf[16], buf[17], buf[18], buf[19], - buf[20], buf[21], buf[22], buf[23], - buf[24], buf[25], buf[26], buf[27], - buf[28], buf[29], buf[30], buf[31], - buf[32], buf[33], buf[34], buf[35], - buf[36], buf[37], buf[38], buf[39], - buf[40], buf[41], buf[42], buf[43], - buf[44], buf[45], buf[46], buf[47], - buf[48], buf[49], buf[50], buf[51], - buf[52], buf[53], buf[54], buf[55], - buf[56], buf[57], buf[58], buf[59], - buf[60], buf[61], buf[62], buf[63]); + fbtft_write_register_64(par, i, buf); + } else if (val & FBTFT_OF_INIT_DELAY) { fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "init: msleep(%u)\n", val & 0xFFFF); @@ -996,23 +1003,7 @@ int fbtft_init_display(struct fbtft_par *par) } buf[j++] = par->init_sequence[i++]; } - par->fbtftops.write_register(par, j, - buf[0], buf[1], buf[2], buf[3], - buf[4], buf[5], buf[6], buf[7], - buf[8], buf[9], buf[10], buf[11], - buf[12], buf[13], buf[14], buf[15], - buf[16], buf[17], buf[18], buf[19], - buf[20], buf[21], buf[22], buf[23], - buf[24], buf[25], buf[26], buf[27], - buf[28], buf[29], buf[30], buf[31], - buf[32], buf[33], buf[34], buf[35], - buf[36], buf[37], buf[38], buf[39], - buf[40], buf[41], buf[42], buf[43], - buf[44], buf[45], buf[46], buf[47], - buf[48], buf[49], buf[50], buf[51], - buf[52], buf[53], buf[54], buf[55], - buf[56], buf[57], buf[58], buf[59], - buf[60], buf[61], buf[62], buf[63]); + fbtft_write_register_64(par, j, buf); break; case -2: i++;