Merge tag 'bsd-user-arm-pull-request' of gitlab.com:bsdimp/qemu into staging

bsd-user: arm (32-bit) support

This series of patches brings in 32-bit arm support for bsd-user.  It implements
all the bits needed to do image activation, signal handling, stack management
and threading. This allows us to get to the "Hello World" level. The arm and x86
code are now the same as in the bsd-user fork. For full context, the fork is at
https://github.com/qemu-bsd-user/qemu-bsd-user/tree/blitz (though the the recent
sig{bus,segv} needed updates are incomplete).

v5 changes:
   o Moved to using the CPUArchState typedef and move
     set_sigtramp_args, get_mcontext, set_mcontext, and
     get_ucontext_sigreturn prototypes to
     bsd-user/freebsd/target_os_ucontext.h
   o Fix issues with arm's set_mcontext related to masking
     and remove an unnecessary check.

We're down to only one hunk needing review:
    bsd-user/arm/target_arch_signal.c: arm set_mcontext

Warnings that should be ignored:
   o make checkpatch has a couple of complaints about the comments for the
     signal trampoline, since it's a false positive IMHO.
WARNING: Block comments use a leading /* on a separate line
+    /* 8 */ sys_sigreturn,
WARNING: Block comments use a leading /* on a separate line
+    /* 9 */ sys_exit

# gpg: Signature made Fri 07 Jan 2022 11:36:37 PM PST
# gpg:                using RSA key 2035F894B00AA3CF7CCDE1B76C1CD1287DB01100
# gpg: Good signature from "Warner Losh <wlosh@netflix.com>" [unknown]
# gpg:                 aka "Warner Losh <imp@bsdimp.com>" [unknown]
# gpg:                 aka "Warner Losh <imp@freebsd.org>" [unknown]
# gpg:                 aka "Warner Losh <imp@village.org>" [unknown]
# gpg:                 aka "Warner Losh <wlosh@bsdimp.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2035 F894 B00A A3CF 7CCD  E1B7 6C1C D128 7DB0 1100

* tag 'bsd-user-arm-pull-request' of gitlab.com:bsdimp/qemu: (37 commits)
  bsd-user: add arm target build
  bsd-user/freebsd/target_os_ucontext.h: Require TARGET_*CONTEXT_SIZE
  bsd-user/arm/signal.c: arm get_ucontext_sigreturn
  bsd-user/arm/signal.c: arm set_mcontext
  bsd-user/arm/signal.c: arm get_mcontext
  bsd-user/arm/signal.c: arm set_sigtramp_args
  bsd-user/arm/target_arch_signal.h: Define size of *context_t
  bsd-user/arm/target_arch_signal.h: arm machine context and trapframe for signals
  bsd-user/arm/target_arch_signal.h: arm specific signal registers and stack
  bsd-user/arm/target_arch_elf.h: arm get_hwcap2 impl
  bsd-user/arm/target_arch_elf.h: arm get hwcap
  bsd-user/arm/target_arch_elf.h: arm defines for ELF
  bsd-user/arm/target_arch_thread.h: Routines to create and switch to a thread
  bsd-user/arm/target_arch_sigtramp.h: Signal Trampoline for arm
  bsd-user/arm/target_arch_vmparam.h: Parameters for arm address space
  bsd-user/arm/target_arch_reg.h: Implement core dump register copying
  bsd-user/arm/target_arch_cpu.h: Implement system call dispatch
  bsd-user/arm/target_arch_cpu.h: Implement data abort exceptions
  bsd-user/arm/target_arch_cpu.h: Implement trivial EXCP exceptions
  bsd-user/arm/target_arch_cpu.h: Dummy target_cpu_loop implementation
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 82 insertions, 0 deletions

diff --git a/bsd-user/arm/target_arch_thread.h b/bsd-user/arm/target_arch_thread.h
new file mode 100644
index 0000000000..11c7f76583
--- /dev/null
+++ b/bsd-user/arm/target_arch_thread.h
@@ -0,0 +1,82 @@
+/*
+ *  arm thread support
+ *
+ *  Copyright (c) 2013 Stacey D. Son
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _TARGET_ARCH_THREAD_H_
+#define _TARGET_ARCH_THREAD_H_
+
+/* Compare to arm/arm/vm_machdep.c cpu_set_upcall_kse() */
+static inline void target_thread_set_upcall(CPUARMState *env, abi_ulong entry,
+    abi_ulong arg, abi_ulong stack_base, abi_ulong stack_size)
+{
+    abi_ulong sp;
+
+    /*
+     * Make sure the stack is properly aligned.
+     * arm/include/param.h (STACKLIGN() macro)
+     */
+    sp = (u_int)(stack_base + stack_size) & ~0x7;
+
+    /* sp = stack base */
+    env->regs[13] = sp;
+    /* pc = start function entry */
+    env->regs[15] = entry & 0xfffffffe;
+    /* r0 = arg */
+    env->regs[0] = arg;
+    env->spsr = ARM_CPU_MODE_USR;
+    /*
+     * Thumb mode is encoded by the low bit in the entry point (since ARM can't
+     * execute at odd addresses). When it's set, set the Thumb bit (T) in the
+     * CPSR.
+     */
+    cpsr_write(env, (entry & 1) * CPSR_T, CPSR_T, CPSRWriteByInstr);
+}
+
+static inline void target_thread_init(struct target_pt_regs *regs,
+        struct image_info *infop)
+{
+    abi_long stack = infop->start_stack;
+    memset(regs, 0, sizeof(*regs));
+    regs->ARM_cpsr = ARM_CPU_MODE_USR;
+    /*
+     * Thumb mode is encoded by the low bit in the entry point (since ARM can't
+     * execute at odd addresses). When it's set, set the Thumb bit (T) in the
+     * CPSR.
+     */
+    if (infop->entry & 1) {
+        regs->ARM_cpsr |= CPSR_T;
+    }
+    regs->ARM_pc = infop->entry & 0xfffffffe;
+    regs->ARM_sp = stack;
+    if (bsd_type == target_freebsd) {
+        regs->ARM_lr = infop->entry & 0xfffffffe;
+    }
+    /*
+     * FreeBSD kernel passes the ps_strings pointer in r0. This is used by some
+     * programs to set status messages that we see in ps. bsd-user doesn't
+     * support that functionality, so it's ignored. When set to 0, FreeBSD's csu
+     * code ignores it. For the static case, r1 and r2 are effectively ignored
+     * by the csu __startup() routine. For the dynamic case, rtld saves r0 but
+     * generates r1 and r2 and passes them into the csu _startup.
+     *
+     * r0 ps_strings 0 passed since ps arg setting not supported
+     * r1 obj_main   ignored by _start(), so 0 passed
+     * r2 cleanup    generated by rtld or ignored by _start(), so 0 passed
+     */
+}
+
+#endif /* !_TARGET_ARCH_THREAD_H_ */