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From:   Evgeniy Baskov <baskov@ispras.ru>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Evgeniy Baskov <baskov@ispras.ru>, Borislav Petkov <bp@alien8.de>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alexey Khoroshilov <khoroshilov@ispras.ru>,
        Peter Jones <pjones@redhat.com>, lvc-project@linuxtesting.org,
        x86@kernel.org, linux-efi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH v2 11/23] x86/boot: Make console interface more abstract
Date:   Tue, 25 Oct 2022 17:12:49 +0300
Message-Id: <8052eb0bfd066a9d11c7f03f8eb03da0648bb643.1666705333.git.baskov@ispras.ru>
In-Reply-To: <cover.1666705333.git.baskov@ispras.ru>
References: <cover.1666705333.git.baskov@ispras.ru>
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To be able to extract kernel from EFI, console output functions
need to be replaceable by alternative implementations.

Make all of those functions pointers.
Move serial console code to separate file.

Signed-off-by: Evgeniy Baskov <baskov@ispras.ru>
---
 arch/x86/boot/compressed/Makefile |   2 +-
 arch/x86/boot/compressed/misc.c   | 109 +------------------------
 arch/x86/boot/compressed/misc.h   |   9 ++-
 arch/x86/boot/compressed/putstr.c | 130 ++++++++++++++++++++++++++++++
 4 files changed, 139 insertions(+), 111 deletions(-)
 create mode 100644 arch/x86/boot/compressed/putstr.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 64de6c2b1740..f79273f46cc7 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -93,7 +93,7 @@ $(obj)/misc.o: $(obj)/../voffset.h
 
 vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/kernel_info.o $(obj)/head_$(BITS).o \
 	$(obj)/misc.o $(obj)/string.o $(obj)/cmdline.o $(obj)/error.o \
-	$(obj)/piggy.o $(obj)/cpuflags.o
+	$(obj)/piggy.o $(obj)/cpuflags.o $(obj)/putstr.o
 
 vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
 vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 0c7ec290044d..aa4a22bc9cf9 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -53,13 +53,6 @@ struct port_io_ops pio_ops;
 memptr free_mem_ptr;
 memptr free_mem_end_ptr;
 
-static char *vidmem;
-static int vidport;
-
-/* These might be accessed before .bss is cleared, so use .data instead. */
-static int lines __section(".data");
-static int cols __section(".data");
-
 #ifdef CONFIG_KERNEL_GZIP
 #include "../../../../lib/decompress_inflate.c"
 #endif
@@ -92,95 +85,6 @@ static int cols __section(".data");
  * ../header.S.
  */
 
-static void scroll(void)
-{
-	int i;
-
-	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
-	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
-		vidmem[i] = ' ';
-}
-
-#define XMTRDY          0x20
-
-#define TXR             0       /*  Transmit register (WRITE) */
-#define LSR             5       /*  Line Status               */
-static void serial_putchar(int ch)
-{
-	unsigned timeout = 0xffff;
-
-	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
-		cpu_relax();
-
-	outb(ch, early_serial_base + TXR);
-}
-
-void __putstr(const char *s)
-{
-	int x, y, pos;
-	char c;
-
-	if (early_serial_base) {
-		const char *str = s;
-		while (*str) {
-			if (*str == '\n')
-				serial_putchar('\r');
-			serial_putchar(*str++);
-		}
-	}
-
-	if (lines == 0 || cols == 0)
-		return;
-
-	x = boot_params->screen_info.orig_x;
-	y = boot_params->screen_info.orig_y;
-
-	while ((c = *s++) != '\0') {
-		if (c == '\n') {
-			x = 0;
-			if (++y >= lines) {
-				scroll();
-				y--;
-			}
-		} else {
-			vidmem[(x + cols * y) * 2] = c;
-			if (++x >= cols) {
-				x = 0;
-				if (++y >= lines) {
-					scroll();
-					y--;
-				}
-			}
-		}
-	}
-
-	boot_params->screen_info.orig_x = x;
-	boot_params->screen_info.orig_y = y;
-
-	pos = (x + cols * y) * 2;	/* Update cursor position */
-	outb(14, vidport);
-	outb(0xff & (pos >> 9), vidport+1);
-	outb(15, vidport);
-	outb(0xff & (pos >> 1), vidport+1);
-}
-
-void __puthex(unsigned long value)
-{
-	char alpha[2] = "0";
-	int bits;
-
-	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
-		unsigned long digit = (value >> bits) & 0xf;
-
-		if (digit < 0xA)
-			alpha[0] = '0' + digit;
-		else
-			alpha[0] = 'a' + (digit - 0xA);
-
-		__putstr(alpha);
-	}
-}
-
 #ifdef CONFIG_X86_NEED_RELOCS
 static void handle_relocations(void *output, unsigned long output_len,
 			       unsigned long virt_addr)
@@ -406,17 +310,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 
 	sanitize_boot_params(boot_params);
 
-	if (boot_params->screen_info.orig_video_mode == 7) {
-		vidmem = (char *) 0xb0000;
-		vidport = 0x3b4;
-	} else {
-		vidmem = (char *) 0xb8000;
-		vidport = 0x3d4;
-	}
-
-	lines = boot_params->screen_info.orig_video_lines;
-	cols = boot_params->screen_info.orig_video_cols;
-
 	init_default_io_ops();
 
 	/*
@@ -427,7 +320,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	 */
 	early_tdx_detect();
 
-	console_init();
+	init_bare_console();
 
 	/*
 	 * Save RSDP address for later use. Have this after console_init()
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 033db9b536e6..38d31bec062d 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -57,8 +57,8 @@ extern memptr free_mem_end_ptr;
 void *malloc(int size);
 void free(void *where);
 extern struct boot_params *boot_params;
-void __putstr(const char *s);
-void __puthex(unsigned long value);
+extern void (*__putstr)(const char *s);
+extern void (*__puthex)(unsigned long value);
 #define error_putstr(__x)  __putstr(__x)
 #define error_puthex(__x)  __puthex(__x)
 
@@ -128,6 +128,11 @@ static inline void console_init(void)
 { }
 #endif
 
+/* putstr.c */
+void init_bare_console(void);
+void init_console_func(void (*putstr_)(const char *),
+		       void (*puthex_)(unsigned long));
+
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 void sev_enable(struct boot_params *bp);
 void sev_es_shutdown_ghcb(void);
diff --git a/arch/x86/boot/compressed/putstr.c b/arch/x86/boot/compressed/putstr.c
new file mode 100644
index 000000000000..44a4c3dacec5
--- /dev/null
+++ b/arch/x86/boot/compressed/putstr.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "misc.h"
+
+/* These might be accessed before .bss is cleared, so use .data instead. */
+static char *vidmem __section(".data");
+static int vidport __section(".data");
+static int lines __section(".data");
+static int cols __section(".data");
+
+void (*__putstr)(const char *s);
+void (*__puthex)(unsigned long value);
+
+static void putstr(const char *s);
+static void puthex(unsigned long value);
+
+void init_console_func(void (*putstr_)(const char *),
+		       void (*puthex_)(unsigned long))
+{
+	__putstr = putstr_;
+	__puthex = puthex_;
+}
+
+void init_bare_console(void)
+{
+	init_console_func(putstr, puthex);
+
+	if (boot_params->screen_info.orig_video_mode == 7) {
+		vidmem = (char *) 0xb0000;
+		vidport = 0x3b4;
+	} else {
+		vidmem = (char *) 0xb8000;
+		vidport = 0x3d4;
+	}
+
+	lines = boot_params->screen_info.orig_video_lines;
+	cols = boot_params->screen_info.orig_video_cols;
+
+	console_init();
+}
+
+static void scroll(void)
+{
+	int i;
+
+	memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2);
+	for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2)
+		vidmem[i] = ' ';
+}
+
+#define XMTRDY          0x20
+
+#define TXR             0       /*  Transmit register (WRITE) */
+#define LSR             5       /*  Line Status               */
+
+static void serial_putchar(int ch)
+{
+	unsigned int timeout = 0xffff;
+
+	while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
+		cpu_relax();
+
+	outb(ch, early_serial_base + TXR);
+}
+
+static void putstr(const char *s)
+{
+	int x, y, pos;
+	char c;
+
+	if (early_serial_base) {
+		const char *str = s;
+
+		while (*str) {
+			if (*str == '\n')
+				serial_putchar('\r');
+			serial_putchar(*str++);
+		}
+	}
+
+	if (lines == 0 || cols == 0)
+		return;
+
+	x = boot_params->screen_info.orig_x;
+	y = boot_params->screen_info.orig_y;
+
+	while ((c = *s++) != '\0') {
+		if (c == '\n') {
+			x = 0;
+			if (++y >= lines) {
+				scroll();
+				y--;
+			}
+		} else {
+			vidmem[(x + cols * y) * 2] = c;
+			if (++x >= cols) {
+				x = 0;
+				if (++y >= lines) {
+					scroll();
+					y--;
+				}
+			}
+		}
+	}
+
+	boot_params->screen_info.orig_x = x;
+	boot_params->screen_info.orig_y = y;
+
+	pos = (x + cols * y) * 2;	/* Update cursor position */
+	outb(14, vidport);
+	outb(0xff & (pos >> 9), vidport+1);
+	outb(15, vidport);
+	outb(0xff & (pos >> 1), vidport+1);
+}
+
+static void puthex(unsigned long value)
+{
+	char alpha[2] = "0";
+	int bits;
+
+	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
+		unsigned long digit = (value >> bits) & 0xf;
+
+		if (digit < 0xA)
+			alpha[0] = '0' + digit;
+		else
+			alpha[0] = 'a' + (digit - 0xA);
+
+		putstr(alpha);
+	}
+}
-- 
2.37.4