Date: Wed, 14 Mar 2018 07:30:58 +0000 (UTC) From: Eitan Adler <eadler@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r330913 - stable/11/sys/dev/syscons Message-ID: <201803140730.w2E7Uw8L062312@repo.freebsd.org>
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Author: eadler Date: Wed Mar 14 07:30:58 2018 New Revision: 330913 URL: https://svnweb.freebsd.org/changeset/base/330913 Log: MFC r314641,r314646,r314997,r315390: Colorize syscons kernel console output according to a table indexed by the CPU number. This was originally for debugging near-deadlock conditions where multiple CPUs either deadlock or scramble each other's output trying to report the problem, but I found it interesting and sometimes useful for ordinary kernel messages. Ordinary kernel messages shouldn't be interleaved, but if they are then the colorization makes them readable even if the interleaving is for every character (provided the CPU printing each message doesn't change). The default colors are 8-15 starting at 15 (bright white on black) for CPU 0 and repeating every 8 CPUs. This works best with 8 CPUs. Non-bright colors and nonzero background colors need special configuration to avoid unreadable and ugly combinations so are not configured by default. The next bright color after 15 is 8 (bright black = dark gray) is not very readable but is the only other color used with 2 CPUs. After that the next bright color is 9 (bright blue) which is not much brighter than bright black, but is used with 3+ CPUs. Other bright colors are brighter. Colorization is configured by default so that it gets tested. It can only be turned off by configuring SC_KERNEL_CONS_ATTR to anything other than FG_WHITE. After booting, all colors can be changed using the syscons.kattr sysctl. This is a SYSCTL_OPAQUE, and no utility is provided to change it (sysctl only displays it). The default colors work in all VGA modes that I could test. In 2-color graphics modes, all 8 bright colors are displayed as bright white, so the colorization has no effect, but anything with a nonzero background gives white on white unless the foreground is zero. I don't have an mono or VGA grayscale hardware to test on. Support for mono mode seems to have never worked right in syscons (I think bright white gives white underline with either bold or bright), but VGA grayscale should work better than 2-color graphics. Implement ec_putc() (emergency kernel [syscons] console putc()) and use it in emergency in sc_cnputc(). Locking fixes in sc_cnputc() previously turned off normal output in near-deadlock conditions and added deferred output which might never be completed. Emergency output goes to the frame buffer using sufficiently atomic non-blocking writes if the console is in text mode (in graphics mode, nothing is done, modulo races setting the graphics mode bit). Screen updates overwrite the emergency output if the emergency condition clears enough to reach them. ec_putc() also works for "early" console output in normal x86 text mode as soon as this mode is initialized (if ever). This uses a hard-coded x86 frame buffer address before cninit() and a hopefully MI address after cninit(). But non-x86 is more likely to not support text mode, when ec_putc() will be null. ec_putc() has no dependencies of syscons before cninit(), and only has them later to track syscons' mode changes. This commit doesn't attach ec_putc() for early use. To test emergency use, put a breakpoint in central syscons output code like sc_puts() and do some user output. The system used to race or deadlock in ddb output soon after entry to ddb. The locking fixes deferred the output until after leaving ddb, so ddb was unusable and you had to try typing c[ontinue] blindly until it exited, or better use a serial console in parallel. Now the output goes to a window in the middle 2/3 of the screen. Scrolling is circular and there is no cursor, but otherwise ec_putc() provides full dumb terminal functionality and very fast output that hides artificates from dumb overwrites. Modified: stable/11/sys/dev/syscons/scterm-teken.c stable/11/sys/dev/syscons/syscons.c stable/11/sys/dev/syscons/syscons.h Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/dev/syscons/scterm-teken.c ============================================================================== --- stable/11/sys/dev/syscons/scterm-teken.c Wed Mar 14 07:16:29 2018 (r330912) +++ stable/11/sys/dev/syscons/scterm-teken.c Wed Mar 14 07:30:58 2018 (r330913) @@ -178,7 +178,7 @@ scteken_puts(scr_stat *scp, u_char *buf, int len, int if (kernel) { /* Use special colors for kernel messages. */ backup = *teken_get_curattr(&ts->ts_teken); - scteken_revattr(SC_KERNEL_CONS_ATTR, &kattr); + scteken_revattr(sc_kattr(), &kattr); teken_set_curattr(&ts->ts_teken, &kattr); teken_input(&ts->ts_teken, buf, len); teken_set_curattr(&ts->ts_teken, &backup); Modified: stable/11/sys/dev/syscons/syscons.c ============================================================================== --- stable/11/sys/dev/syscons/syscons.c Wed Mar 14 07:16:29 2018 (r330912) +++ stable/11/sys/dev/syscons/syscons.c Wed Mar 14 07:30:58 2018 (r330913) @@ -53,6 +53,7 @@ __FBSDID("$FreeBSD$"); #include <sys/lock.h> #include <sys/malloc.h> #include <sys/mutex.h> +#include <sys/pcpu.h> #include <sys/priv.h> #include <sys/proc.h> #include <sys/random.h> @@ -102,6 +103,8 @@ static default_attr user_default = { SC_NORM_REV_ATTR, }; +static u_char sc_kattrtab[MAXCPU]; + static int sc_console_unit = -1; static int sc_saver_keyb_only = 1; static scr_stat *sc_console; @@ -143,6 +146,8 @@ static int sc_no_suspend_vtswitch = 0; static int sc_susp_scr; static SYSCTL_NODE(_hw, OID_AUTO, syscons, CTLFLAG_RD, 0, "syscons"); +SYSCTL_OPAQUE(_hw_syscons, OID_AUTO, kattr, CTLFLAG_RW, + &sc_kattrtab, sizeof(sc_kattrtab), "CU", "kernel console attributes"); static SYSCTL_NODE(_hw_syscons, OID_AUTO, saver, CTLFLAG_RD, 0, "saver"); SYSCTL_INT(_hw_syscons_saver, OID_AUTO, keybonly, CTLFLAG_RW, &sc_saver_keyb_only, 0, "screen saver interrupted by input only"); @@ -263,6 +268,62 @@ static struct cdevsw consolectl_devsw = { .d_name = "consolectl", }; +/* ec -- emergency console. */ + +static u_int ec_scroffset; + +static void +ec_putc(int c) +{ + uintptr_t fb; + u_short *scrptr; + u_int ind; + int attr, column, mysize, width, xsize, yborder, ysize; + + if (c < 0 || c > 0xff || c == '\a') + return; + if (sc_console == NULL) { +#if !defined(__amd64__) && !defined(__i386__) + return; +#endif + /* + * This is enough for ec_putc() to work very early on x86 + * if the kernel starts in normal color text mode. + */ + fb = 0xb8000; + xsize = 80; + ysize = 25; + } else { + if (main_console.status & GRAPHICS_MODE) + return; + fb = main_console.sc->adp->va_window; + xsize = main_console.xsize; + ysize = main_console.ysize; + } + yborder = ysize / 5; + scrptr = (u_short *)(void *)fb + xsize * yborder; + mysize = xsize * (ysize - 2 * yborder); + do { + ind = ec_scroffset; + column = ind % xsize; + width = (c == '\b' ? -1 : c == '\t' ? (column + 8) & ~7 : + c == '\r' ? -column : c == '\n' ? xsize - column : 1); + if (width == 0 || (width < 0 && ind < -width)) + return; + } while (atomic_cmpset_rel_int(&ec_scroffset, ind, ind + width) == 0); + if (c == '\b' || c == '\r') + return; + if (c == '\n') + ind += xsize; /* XXX clearing from new pos is not atomic */ + + attr = sc_kattr(); + if (c == '\t' || c == '\n') + c = ' '; + do + scrptr[ind++ % mysize] = (attr << 8) | c; + while (--width != 0); +} + int sc_probe_unit(int unit, int flags) { @@ -1859,10 +1920,13 @@ sc_cnputc(struct consdev *cd, int c) sc_cnputc_log[head % sizeof(sc_cnputc_log)] = c; /* - * If we couldn't open, return to defer output. + * If we couldn't open, do special reentrant output and return to defer + * normal output. */ - if (!st.scr_opened) + if (!st.scr_opened) { + ec_putc(c); return; + } #ifndef SC_NO_HISTORY if (scp == scp->sc->cur_scp && scp->status & SLKED) { @@ -3009,8 +3073,16 @@ scinit(int unit, int flags) int i; /* one time initialization */ - if (init_done == COLD) + if (init_done == COLD) { sc_get_bios_values(&bios_value); + for (i = 0; i < nitems(sc_kattrtab); i++) { +#if SC_KERNEL_CONS_ATTR == FG_WHITE + sc_kattrtab[i] = 8 + (i + FG_WHITE) % 8U; +#else + sc_kattrtab[i] = SC_KERNEL_CONS_ATTR; +#endif + } + } init_done = WARM; /* @@ -4024,6 +4096,12 @@ sc_bell(scr_stat *scp, int pitch, int duration) pitch *= 2; sysbeep(1193182 / pitch, duration); } +} + +int +sc_kattr(void) +{ + return (sc_kattrtab[PCPU_GET(cpuid) % nitems(sc_kattrtab)]); } static void Modified: stable/11/sys/dev/syscons/syscons.h ============================================================================== --- stable/11/sys/dev/syscons/syscons.h Wed Mar 14 07:16:29 2018 (r330912) +++ stable/11/sys/dev/syscons/syscons.h Wed Mar 14 07:30:58 2018 (r330913) @@ -591,6 +591,7 @@ void sc_paste(scr_stat *scp, const u_char *p, int cou void sc_respond(scr_stat *scp, const u_char *p, int count, int wakeup); void sc_bell(scr_stat *scp, int pitch, int duration); +int sc_kattr(void); /* schistory.c */ #ifndef SC_NO_HISTORY
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