From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- arch/m68k/atari/debug.c | 329 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 329 insertions(+) create mode 100644 arch/m68k/atari/debug.c (limited to 'arch/m68k/atari/debug.c') diff --git a/arch/m68k/atari/debug.c b/arch/m68k/atari/debug.c new file mode 100644 index 000000000..03cb5e08d --- /dev/null +++ b/arch/m68k/atari/debug.c @@ -0,0 +1,329 @@ +/* + * linux/arch/m68k/atari/debug.c + * + * Atari debugging and serial console stuff + * + * Assembled of parts of former atari/config.c 97-12-18 by Roman Hodek + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + +#include +#include +#include +#include +#include +#include + +#include +#include + +/* Can be set somewhere, if a SCC master reset has already be done and should + * not be repeated; used by kgdb */ +int atari_SCC_reset_done; +EXPORT_SYMBOL(atari_SCC_reset_done); + +static struct console atari_console_driver = { + .name = "debug", + .flags = CON_PRINTBUFFER, + .index = -1, +}; + + +static inline void ata_mfp_out(char c) +{ + while (!(st_mfp.trn_stat & 0x80)) /* wait for tx buf empty */ + barrier(); + st_mfp.usart_dta = c; +} + +static void atari_mfp_console_write(struct console *co, const char *str, + unsigned int count) +{ + while (count--) { + if (*str == '\n') + ata_mfp_out('\r'); + ata_mfp_out(*str++); + } +} + +static inline void ata_scc_out(char c) +{ + do { + MFPDELAY(); + } while (!(atari_scc.cha_b_ctrl & 0x04)); /* wait for tx buf empty */ + MFPDELAY(); + atari_scc.cha_b_data = c; +} + +static void atari_scc_console_write(struct console *co, const char *str, + unsigned int count) +{ + while (count--) { + if (*str == '\n') + ata_scc_out('\r'); + ata_scc_out(*str++); + } +} + +static inline void ata_midi_out(char c) +{ + while (!(acia.mid_ctrl & ACIA_TDRE)) /* wait for tx buf empty */ + barrier(); + acia.mid_data = c; +} + +static void atari_midi_console_write(struct console *co, const char *str, + unsigned int count) +{ + while (count--) { + if (*str == '\n') + ata_midi_out('\r'); + ata_midi_out(*str++); + } +} + +static int ata_par_out(char c) +{ + unsigned char tmp; + /* This a some-seconds timeout in case no printer is connected */ + unsigned long i = loops_per_jiffy > 1 ? loops_per_jiffy : 10000000/HZ; + + while ((st_mfp.par_dt_reg & 1) && --i) /* wait for BUSY == L */ + ; + if (!i) + return 0; + + sound_ym.rd_data_reg_sel = 15; /* select port B */ + sound_ym.wd_data = c; /* put char onto port */ + sound_ym.rd_data_reg_sel = 14; /* select port A */ + tmp = sound_ym.rd_data_reg_sel; + sound_ym.wd_data = tmp & ~0x20; /* set strobe L */ + MFPDELAY(); /* wait a bit */ + sound_ym.wd_data = tmp | 0x20; /* set strobe H */ + return 1; +} + +static void atari_par_console_write(struct console *co, const char *str, + unsigned int count) +{ + static int printer_present = 1; + + if (!printer_present) + return; + + while (count--) { + if (*str == '\n') { + if (!ata_par_out('\r')) { + printer_present = 0; + return; + } + } + if (!ata_par_out(*str++)) { + printer_present = 0; + return; + } + } +} + +#if 0 +int atari_mfp_console_wait_key(struct console *co) +{ + while (!(st_mfp.rcv_stat & 0x80)) /* wait for rx buf filled */ + barrier(); + return st_mfp.usart_dta; +} + +int atari_scc_console_wait_key(struct console *co) +{ + do { + MFPDELAY(); + } while (!(atari_scc.cha_b_ctrl & 0x01)); /* wait for rx buf filled */ + MFPDELAY(); + return atari_scc.cha_b_data; +} + +int atari_midi_console_wait_key(struct console *co) +{ + while (!(acia.mid_ctrl & ACIA_RDRF)) /* wait for rx buf filled */ + barrier(); + return acia.mid_data; +} +#endif + +/* + * The following two functions do a quick'n'dirty initialization of the MFP or + * SCC serial ports. They're used by the debugging interface, kgdb, and the + * serial console code. + */ +static void __init atari_init_mfp_port(int cflag) +{ + /* + * timer values for 1200...115200 bps; > 38400 select 110, 134, or 150 + * bps, resp., and work only correct if there's a RSVE or RSSPEED + */ + static int baud_table[9] = { 16, 11, 8, 4, 2, 1, 175, 143, 128 }; + int baud = cflag & CBAUD; + int parity = (cflag & PARENB) ? ((cflag & PARODD) ? 0x04 : 0x06) : 0; + int csize = ((cflag & CSIZE) == CS7) ? 0x20 : 0x00; + + if (cflag & CBAUDEX) + baud += B38400; + if (baud < B1200 || baud > B38400+2) + baud = B9600; /* use default 9600bps for non-implemented rates */ + baud -= B1200; /* baud_table[] starts at 1200bps */ + + st_mfp.trn_stat &= ~0x01; /* disable TX */ + st_mfp.usart_ctr = parity | csize | 0x88; /* 1:16 clk mode, 1 stop bit */ + st_mfp.tim_ct_cd &= 0x70; /* stop timer D */ + st_mfp.tim_dt_d = baud_table[baud]; + st_mfp.tim_ct_cd |= 0x01; /* start timer D, 1:4 */ + st_mfp.trn_stat |= 0x01; /* enable TX */ +} + +#define SCC_WRITE(reg, val) \ + do { \ + atari_scc.cha_b_ctrl = (reg); \ + MFPDELAY(); \ + atari_scc.cha_b_ctrl = (val); \ + MFPDELAY(); \ + } while (0) + +/* loops_per_jiffy isn't initialized yet, so we can't use udelay(). This does a + * delay of ~ 60us. */ +#define LONG_DELAY() \ + do { \ + int i; \ + for (i = 100; i > 0; --i) \ + MFPDELAY(); \ + } while (0) + +static void __init atari_init_scc_port(int cflag) +{ + static int clksrc_table[9] = + /* reg 11: 0x50 = BRG, 0x00 = RTxC, 0x28 = TRxC */ + { 0x50, 0x50, 0x50, 0x50, 0x50, 0x50, 0x50, 0x00, 0x00 }; + static int brgsrc_table[9] = + /* reg 14: 0 = RTxC, 2 = PCLK */ + { 2, 2, 2, 2, 2, 2, 0, 2, 2 }; + static int clkmode_table[9] = + /* reg 4: 0x40 = x16, 0x80 = x32, 0xc0 = x64 */ + { 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0xc0, 0x80 }; + static int div_table[9] = + /* reg12 (BRG low) */ + { 208, 138, 103, 50, 24, 11, 1, 0, 0 }; + + int baud = cflag & CBAUD; + int clksrc, clkmode, div, reg3, reg5; + + if (cflag & CBAUDEX) + baud += B38400; + if (baud < B1200 || baud > B38400+2) + baud = B9600; /* use default 9600bps for non-implemented rates */ + baud -= B1200; /* tables starts at 1200bps */ + + clksrc = clksrc_table[baud]; + clkmode = clkmode_table[baud]; + div = div_table[baud]; + if (ATARIHW_PRESENT(TT_MFP) && baud >= 6) { + /* special treatment for TT, where rates >= 38400 are done via TRxC */ + clksrc = 0x28; /* TRxC */ + clkmode = baud == 6 ? 0xc0 : + baud == 7 ? 0x80 : /* really 76800bps */ + 0x40; /* really 153600bps */ + div = 0; + } + + reg3 = (cflag & CSIZE) == CS8 ? 0xc0 : 0x40; + reg5 = (cflag & CSIZE) == CS8 ? 0x60 : 0x20 | 0x82 /* assert DTR/RTS */; + + (void)atari_scc.cha_b_ctrl; /* reset reg pointer */ + SCC_WRITE(9, 0xc0); /* reset */ + LONG_DELAY(); /* extra delay after WR9 access */ + SCC_WRITE(4, (cflag & PARENB) ? ((cflag & PARODD) ? 0x01 : 0x03) + : 0 | 0x04 /* 1 stopbit */ | clkmode); + SCC_WRITE(3, reg3); + SCC_WRITE(5, reg5); + SCC_WRITE(9, 0); /* no interrupts */ + LONG_DELAY(); /* extra delay after WR9 access */ + SCC_WRITE(10, 0); /* NRZ mode */ + SCC_WRITE(11, clksrc); /* main clock source */ + SCC_WRITE(12, div); /* BRG value */ + SCC_WRITE(13, 0); /* BRG high byte */ + SCC_WRITE(14, brgsrc_table[baud]); + SCC_WRITE(14, brgsrc_table[baud] | (div ? 1 : 0)); + SCC_WRITE(3, reg3 | 1); + SCC_WRITE(5, reg5 | 8); + + atari_SCC_reset_done = 1; +} + +static void __init atari_init_midi_port(int cflag) +{ + int baud = cflag & CBAUD; + int csize = ((cflag & CSIZE) == CS8) ? 0x10 : 0x00; + /* warning 7N1 isn't possible! (instead 7O2 is used...) */ + int parity = (cflag & PARENB) ? ((cflag & PARODD) ? 0x0c : 0x08) : 0x04; + int div; + + /* 4800 selects 7812.5, 115200 selects 500000, all other (incl. 9600 as + * default) the standard MIDI speed 31250. */ + if (cflag & CBAUDEX) + baud += B38400; + if (baud == B4800) + div = ACIA_DIV64; /* really 7812.5 bps */ + else if (baud == B38400+2 /* 115200 */) + div = ACIA_DIV1; /* really 500 kbps (does that work??) */ + else + div = ACIA_DIV16; /* 31250 bps, standard for MIDI */ + + /* RTS low, ints disabled */ + acia.mid_ctrl = div | csize | parity | + ((atari_switches & ATARI_SWITCH_MIDI) ? + ACIA_RHTID : ACIA_RLTID); +} + +static int __init atari_debug_setup(char *arg) +{ + bool registered; + + if (!MACH_IS_ATARI) + return 0; + + if (!strcmp(arg, "ser")) + /* defaults to ser2 for a Falcon and ser1 otherwise */ + arg = MACH_IS_FALCON ? "ser2" : "ser1"; + + registered = !!atari_console_driver.write; + if (!strcmp(arg, "ser1")) { + /* ST-MFP Modem1 serial port */ + atari_init_mfp_port(B9600|CS8); + atari_console_driver.write = atari_mfp_console_write; + } else if (!strcmp(arg, "ser2")) { + /* SCC Modem2 serial port */ + atari_init_scc_port(B9600|CS8); + atari_console_driver.write = atari_scc_console_write; + } else if (!strcmp(arg, "midi")) { + /* MIDI port */ + atari_init_midi_port(B9600|CS8); + atari_console_driver.write = atari_midi_console_write; + } else if (!strcmp(arg, "par")) { + /* parallel printer */ + atari_turnoff_irq(IRQ_MFP_BUSY); /* avoid ints */ + sound_ym.rd_data_reg_sel = 7; /* select mixer control */ + sound_ym.wd_data = 0xff; /* sound off, ports are output */ + sound_ym.rd_data_reg_sel = 15; /* select port B */ + sound_ym.wd_data = 0; /* no char */ + sound_ym.rd_data_reg_sel = 14; /* select port A */ + sound_ym.wd_data = sound_ym.rd_data_reg_sel | 0x20; /* strobe H */ + atari_console_driver.write = atari_par_console_write; + } + if (atari_console_driver.write && !registered) + register_console(&atari_console_driver); + + return 0; +} + +early_param("debug", atari_debug_setup); -- cgit v1.3.1